I have had this since day 1(Cubase 8), and I still suffer from it, even in 10.5.20.
Opening/closing/opening another project will crash Cubase at some point. Never been able to open/close/open say 5 projects one after another without crashing or freezing.
And quitting /restarting between projects(for example, when overdubbing lead vocals)is kinda dumb. And slow.