After losing four straight games, the Cobras went on a four-match winning streak, only to have their fourth win against the Hawks taken off them when it was revealed they fielded an ineligible player.
Both the Cobras and the wooden spoon Bears struggled for numbers after that, defaulting both their final round robin games and the weekend quarterfinals.
On their Facebook page, the TRL thanked the Cobras and Bears for taking part in the Premiership.
"Although things did not finish as well as you both would have liked, there was a lot to like from both teams who managed to win some magnificent games throughout the season.
"It is hoped both teams regroup and come back even stronger in 2019."
Boxon are guaranteed to have the top tryscorer for the season and likely the leading points scorer as Emitai Logadraudrau sits on 13 tries with the closest players still active being clubmates Jordan Davis and Tautahi Rawiri with seven.
Goal kicker Rawiri will have the opportunity to break the 100-point barrier for the competition as he currently sits on 92.
In the games between the Hawks and Boxon this season, the Hawera side drew first blood at home with a 30-28 win under lights in March at the TSB Hub, scoring the matchwinning try off the final play.
The Boxon got payback in May with a 48-20 win in a day match at the City College grounds, after they blew the scoreline out in the final quarter.
The semifinal will be at Cooks Gardens on Saturday, with a 2.30pm kickoff.