I have a problem with some projects, exiting the full screen mode crashes After Effects (Mac OsX 11.11.1)
What workspace are you using? Does it happen every time or just with a project open? What happens what it crashes? Does it give you error messages? What about crash logs?
I made different tests and it's weird. On the standard workspace I have no problems, it seems it happens every time but only with some projects when I have some scripts docked in the the stacked panels (like the Essential workspace). The log file: After Effects Log.txt - Google Drive