Midi freeze bug

Project session has suddenly stopped allowing me to

delete the midi event recorded or move the midi event or even undo the recording
after playing for 3 to 4 times. i have to restart it again but the same problem happens again.
it was working fine till last night. haven’t changed anything nor i have loaded anything new in the project. its a strange thing and not helping in any way to complete the project I also updated Cubase12 to the latest version but still the same. it didn’t create any crash dump files as it never crashed just hangs that particular midi event and then doesn’t allow me to delete it.

any solution or anybody who has any fix for this would really be helpful i googled the whole day but had no luck till now.

I am on windows 10 pc
thanks in advance.