I’ve been having this issue for a long time now. It only happens when I export long sessions offline (like film works). The point is that Cubase is very stable online, but it crashes with this long sessions. The workaround is being submixing to a group and recording to a track in realtime, but it’s kind of painful.
I just did Render two separate project both around 1h30m long, no issues.
I would suggest trying a mixdown without ASIO Guard, and trying different buffer sizes.
I have noticed some strange behavior on extremely low and high buffer sizes, like 32 and 4096.
I have been having the exact same problem for quite some time and while I found bouncing real time helped, its a temporary fix. Did you ever fix this issue where you are able to bounce offline again without a crash?