Court challenges and lawsuits were the reason. “U.S. District Judge William Conley rejected a request by Democrats and liberal groups to postpone Wisconsin’s election, but ordered that voters have until Monday (today)— six days after the election — to file absentee ballots. And Conley prohibited clerks from starting counts until 4 p.m. today.”
https://wkow.com/2020/04/13/clerks-set-to-count-votes-in-messy-wisconsin-election/
Thank you for the info. So it was based on court challenges that this happened. I had not heard anyone in the media, or anyone here, note that it was highly unusual to not release election returns as votes were counted on election night.