This might help for those having constant freezes in simple tasks in Cubase 10 or 10.5 like I did.
Try disabling all MIDI Sends. There seems to be something wrong with them.
There wasn’t any loop in the project where I found this issue. I could play and hear normally what I was playing, but every time that I was doing a recording of about 2min 15s of piano (classical music with many notes), after pressing stop, Cubase would cut the sound: the MIDI meters were on but I could not hear any more sound. After that, I couldn’t close Cubase or change the sound card: Cubase would freeze.
The steps leading to the audio engine crash (both on 10.0.60 and 10.5.20) were dead simple: arm many midi tracks at once, record 2min, stop.
I was able to isolate the issue: I had 6 MIDI sends that were sending notes to a virtual keyboard plugin. It wasn’t a problem with the plugin itself because I ran the same test with the plugin playing the notes directly (without a MIDI send) and it didn’t freeze. After disabling the MIDI sends, the problem disappeared.