In 2004 it took three recounts for Democrat Christine Gregoire to beat Republican Dino Rossi by just 129 votes after two recounts of more than 2.8 million ballots cast. Rossi won both of the initial tallies. But you are right, in that instance the Democrats had already cheated enough by election night to bring it much closer than the Florida races are now.
Shifting 12.5K would be so brazen, the Senate would be absolutely justified in refusing to seat Nelson.
There are two hail mary passes that the Nelson theft team is pursuing.
1st. They are going to try to convince a Florida Judge to ignore the law and to allow ballots with mismatched signatures to count. (That hearing is on Wednesday.)
2nd. In Broward County, there was an undervote in the Senate race. Scott got about 10K less votes county wide than Desantis and Nelson got about 10K less votes than Gillum.
People are thinking it was due to stupid voters and ballot design.
In Broward, they tucked the Senate race in the bottom left of the ballot:
https://pbs.twimg.com/media/DrbxBZxXcAE7WXq.jpg:large
There were a lot of people that said they missed it.
Their argument would be that if they voted for Democrats elsewhere on the ballot, that we should magically count these votes for Nelson. (They made that argument in Minnesota and Washington.)
However, the fact that the error is distributed almost evenly between Scott and Nelson doesn’t give much hope to the Rats here.