Some Republicans are trying to do "Dump Trump" at convention. I suspect that what they are doing is trying to distance themselves from him so that they can keep House and Senate if he goes down. And they might be wanting to tell the "Tea Party" types a big "I told you so," so they can retake full control of party after the election.
But, my channeling Theodore J. Lowi (who wrote The End of the Republican Era about the breakup of the Republican coalition) leads me to wonder: They might be experimenting with the notion of having different parts of the GOP in charge of Executive and Congress as a way of keeping the different elements of the party together. That is, resolving their factions by having each in charge of different part of government. It might fail, it might work, especially because of the hatred toward Hillary Clinton.