Is this one project in particular that crashes in X3 and is ok in X2? Or is it a number of projects that do it?
I would suggest that if you have one project in particular, it would be extremely useful to raise this with CW and send in the crash reports and perhaps the project itself.
This is one of those situations where we have a role to play in getting X3 the most solid version ever. In your specific case, you should be escalating this to CW.
For the record, and back to your question - no I haven't seen this yet in any of my X2 projects opened in X3. Hopefully you can track it down with tech support and get working again. 3 or 4 crashes per hour would drive me nuts! Best of luck.