The scales continued to climb before officially stopping at 172.7 pounds - a long way over the allowed limit and putting the fight in serious jeopardy.
Jacobs and his team made a deal for the fight to stay on at a new weight of 173 pounds, but Chavez would be slugged US$1 million (NZ$1.5m) of his roughly $3 million paycheck.
Thankfully the 12-round fight will go on, taking place in Phoenix's Talking Stick Resort Arena.
"It doesn't bother us at all. Danny's still gonna beat his a**," Jacobs' manager Keith Connolly told ESPN.
Chavez's last major fight came back in 2017 when he was comprehensively beaten by the dominant Canelo Alvarez.
He fought Evert Bravo in August, scoring a first round knockout against the lesser known opponent.
Jacobs' last fight came against Alvarez, and although he suffered the same fate as Chavez, he made the bout competitive.