This is a longshot, but the crashing the first time then working fine on subsequent loads of Cubase reminds me of an issue I was having (and perhaps still am? – I’m careful not to do the behavior that led to the issue these days) that related to Waves Clarity Vx and Clarity Vx DeReverb a while back. Any chance you’re using those plugins?
FWIW, here is the thread I started on this a while back:
I spent a lot of time with Waves support running tests they asked me to do, trying other tests they’d wanted but that were unworkable on my system, etc. The upshot was, they blamed it on some unknown something on my system because they weren’t seeing it elsewhere, and the support people weren’t allowed to talk to the engineers just based on the information I was providing them.