Put it down to national pride. Maybe it's fatigue, her sometimes wayward driver, ditching her caddie, the ever-growing commitments as world number one, a brutal schedule or the fact that she might be in the process of changing over to a new equipment sponsor.
Maybe it's all of the above.
There seem to be a number of reasons, or theories, as to why Lydia Ko just couldn't find consistency in the back half of the 2016 LPGA season, her third full year as a professional, but there's a pretty clear marker where her form started to dip and those ever-reliable putts just didn't seem to drop. The Rio Olympics.
The fact she won an Olympic medal seems to have been forgotten after she finished the LPGA season empty-handed on Monday. That's the high expectations the New Zealand public and media seem to have of the teenager. Her success is judged differently to any other New Zealand athlete. It's at an All Blacks level and it's all her own fault.
Ko's main goal of 2016 was claim an Olympic medal in golf's return to the Games since 1904. She wanted to do her country proud, stand on that dais and claim one of those medals. Possibly hear the New Zealand anthem. She didn't go that far, finishing second behind South Korea's Inbee Park, but the medal was all that mattered, the colour didn't.
"You win a gold, silver or bronze medal this week. Sometimes people get carried away and say you 'lost' to someone but, no matter the result, you won," she told Radio Sport after becoming New Zealand's second youngest ever medallist at the Olympics.
She achieved her 2016 goal in August and then that medal seemed to weigh her down for the rest of the season.
"She put so much emphasis into wanting to play well to the point where she was down and determined to win a medal for New Zealand," Ko's coach David Leadbetter told the Herald.
"It was really the highlight of her year. She put a lot into that, even more so than winning a major. After that her travel schedule was incredible. The game is all about momentum and when the momentum goes the other direction, it's sometimes difficult to stop."
After the Olympics, what had been Ko's remarkable run of results began to slip. And again 'slip' by Ko's amazingly high standards. Up until her last win at the Marathon Classic in July, Ko was at a different level. She had 10 top tens in 15 tournaments. Her worst result until that point was tied for 23rd.At the back end of the season she was rarely in contention at the end of the tournament, going five tournaments without a top 10.
She still didn't miss one cut, though a weekend off probably would have been beneficial. From Brazil she went to Canada producing two more top 10s before heading to the Evian Championship in France. Sponsors commitments, and the demands of being world number one and the defending champion started to wear her down.
Leadbetter said you could tell when Ko went to the Evian, the final major of the year, that she was physically drained.
"I remember being at the Evian looking at her teeing off on Thursday and this girl was spent. She'd been doing so much travel, she been trying new equipment out, she'd had these red-eye flights from coast to coast, she'd literally have two days at home and then fly over to France for sponsor commitments with Rolex and Evian who she's contracted to. It was a perfect storm and a ho-hum week for her."
She finished 43rd and failed to find that consistent brilliance for the rest of the season, especially in the final rounds where she didn't have one under-par fourth round in the final five tournaments, something she did 13 times in the 17 events before the Evian. The long season and fact she'd achieved her goal of the year in August were starting to affect her game.
Last weekend it looked like the momentum was back. Ko shot a 62 in the second round to take a three-shot lead and she looked odds-on to claim all three major end of season awards - The Race to the CME Globe, and with it a US$1m bonus, the Rolex Player of the Year title and the prestigious Vare Trophy, which goes to the player with the lowest scoring average across the whole season.
Unfortunately the double bogeys that have crept into her game since September came back and she missed a few simple putts in the third round. On the final Sunday of the season Ariya Jutanugarn, who Ko had to better to have any chance of winning the player of the year and the Race to the CME Globe, finished the stronger to claim the big prizes.
Jutanugarn seemed out of contention after the second round but was11 shots better than Ko over the weekend.
Ko then missed the Vare when playing partner In Gee Chun went birdie-birdie to end her round and win the award by just .013 points. Combined, Ko and Chun took more than 11,500 swings over 166 rounds - and the scoring title came down to one putt.
So that meant on Monday, Ko had nothing to show for the season... except for four trophies, an Olympic medal, three seconds, two thirds, 23 out of 23 cuts made and a touch under US$2.5 in prize money. She also gained five more points towards her claim to make the LPGA Hall of Fame. She has 17 points of the 27 needed to qualify - again she is just 19 - and more than halfway to the Hall of Fame. But there is still that lingering feeling among pundits and fans that she didn't have a great season.
The always positive Ko had a typical Ko take.
"I started (the season) with a bang, played really well and got to have my second major in my career. Just so many highs," Ko told media after her final round of the year.
"Olympics was the biggest goal of mine coming into this year. I got to compete in that and become a (silver) medallist. So many dreams came true.
"It may hurt about what happened right now, but I still feel like it's been an awesome season. I'll give myself an A+."
So she's happy with the year. Why can't we all be? That's the issue with being Lydia Ko. The phenomenal start to her professional career has brought upon huge expectations. She's the female version of Tiger Woods. But for some that isn't enough. She has to be the All Blacks. She has to win every time. Which, in golf, is ridiculous.
Phil Tataurangi, a former professional on the PGA Tour who checks in with Ko several times during the season, said the same happened to Woods at his peak.
"When Tiger was going through his purple patch in the late 90s-early 2000s he was the victim of his own success. The year that he either didn't win a major championship or didn't win player of the year title, through that period of time there wasn't many occasions where one of those two things didn't happen, it was seen as though it was a lesser year. Where those years would go down as career years of anybody else on the PGA Tour - yet they were seen as a lesser year for the standard he had set. Lydia's in that same category."
Since there is no Olympics next year, or the next two after, that must mean the old Lydia will be back once she returns from a well-earned break in February. Well maybe not. Those other issues will still need to be dealt with.
Her driving accuracy has gone from 79.2 percent to 70.9 percent since 2014. That makes sense if she's forgoing accuracy for more distance off the tee but she actually was four yards shorter this year compared to last year - ranking her 126th out of 158th in average distance. Maybe that could be put down to tiredness or unhappiness with her clubs. She's expected to announce in the New Year that she's changing from Callaway to PXG.
PXG is a newcomer in the golf equipment game. Owned by Arizona billionaire Bob Parsons, the company has only a handful of PGA Tour and LPGA pros on their books - the likes of Billy Horschel, Ryan Moore and Charl Schwartzel to name the few. Ko would be the biggest name to sign on.
Who knows if a new driver will help or hinder her game but Zach Johnson recently changed his PXG driver for his old Titleist at the Ryder Cup because he was struggling off the tee.
It could be a risky move for Ko but it will certainly be more beneficial in terms of her ever growing bank balance. The sponsors have started to pile up and with it the money. She's now got deals with Rolex, Lexus, Evian, Nerium skin care, Galvani Tech apparel, Fly 1 Above, Rosemark Grips and ANZ.
Leadbetter says that they'll be looking at her schedule and sponsors commitments for the 2017 season. Being number one in the world means a lot of work off the course.
"There's a lot more stress on her now. The fact that being number one and all the expectations that come with it. All the interviews that come with it. There needs to be a serious look at her scheduling. She didn't overplay but on the other hand when she did play she played a lot and didn't have a whole lot of rest in-between."
"You've got to deal with it. Expectations come with being number one. That's just the way it is."
The main thing to sort out however, since you can't play golf without one, is a caddie. Ko parted ways with regular caddie Australian Jason Hamilton last month after winning 13 titles and two majors together since joining forces at the end of the 2014 season.
She finished the season using several different caddies including South African Gary Matthews, former caddie of Sergio Garcia, over the weekend.
Leadbetter didn't agree with the timing of Hamilton's departure saying it made sense to play out the rest of the season with him.
"It's one of those things you look back at and say 'Ok maybe it wasn't the best thing to do at the time'. Hopefully learn from it and go forward."
He said finding a caddie is priority over the off-season but it seems Ko is still in the early stages of finding someone.
"I'm sure next year, whoever it may be, she'll have a good caddie. Every man and his dog wants to caddie for Lydia. They're going to make a lot of money. She's going to get one of the better caddies whether it's from the LPGA or the PGA tour," Leadbetter told Radio Sport last month.
"She's very easy to work with. She's not overly demanding and she's a pleasure to be around."
Tataurangi said changing a caddie can be good a first but you have to trust you've got the right person carrying your bag when the pressure is on.
"It's like you've had a putter in the bag for a long time and you change it up. The freshness can be worth a couple of shots, a little spring in your step. But when put under the blowtorch of competition, I think the mind likes to go back to familiarity. If there is a little bit of an unknown there, that's just a factor you've got to consciously deal with."
Despite not claiming any big awards this week Ko remains world number one, a position she has held for 57 straight weeks. She's not losing that spot any time soon. At one point this year the margin between her a second placed Brooke Henderson was the biggest ever since the rankings were established in 2006. By the time she tees off in her next tournament, the Australian Open in February, she'll have the third longest streak at number one and will be closing in on Park for fourth in the all-time number of weeks in top spot.
What will have also grown however is the number of weeks since her last tournament win, which came at the Marathon Classic in July. A news website referred to it as a 'title drought'. There's that expectation again.
New season, new clubs, new caddie, new distractions. Right now Ko is enjoying a break and time to reflect on what has been another exceptional year - possibly while wearing that Olympic medal. She's still the best in the world. She's still a teenager. And yes as we found out this year she's human. That's something we should be proud of as a nation.
Lydia Ko in 2016
23 cuts made
1 major victory (ANA Inspiration)
4 LPGA Tour victories
Earnings: US$$2,492,994 (ranked second)
Scoring average: 69.596 (ranked second)
Putting average: 28.31 (ranked first)
Driving distance: 246.729 (ranked 126th)