Crashes after various file open /close with atmos

I´m mixing a stereo version and a Atmos version of the same project. Same song but two different mixes. When i close the Atmos and open the stereo one so i can make changes Cubase hangs on the Windows Wheel. not always , maybe after a few open/close in between .
After this i force quit (ctrl+alt+del) and when i try to reopen Cubase says i dont have a valid licence and it makes all content offline. The only solution is to reboot! Happen a few times today. I need to finish this project
I try to open the Activation manager to see what is activated or nor and is not opening, only after i reboot i can get back to everything as normal.
Anyone experiencing this ?

Cubase 12 Pro version 12.0.40
Windows 10 20h2


Could you provide a DMP file by using Microsoft ProcDump, please?