that is fantastic!
I would even settle for Two & One.
I just replicated the crash and got the same error message!! At least it is repeatable!
For what it's worth, I had two sessions of SWX2017 open on my two screens. I was making a new assembly using a lot of stuff from another assembly. I was using Ctrl+C to copy parts from the old assembly and Ctrl+V to paste them into the new assembly in the other session. So far, so good. BUT when I tried to do the same thing with a subassembly it consistently crashes when trying to paste the subassy into the new assembly. I'm using SP3.0. No, I am not interested in trying to navigate the Knowledge Base. I'll leave that mess to the VARs and others with more patience for this crap than I have.
Jim Wilkinson, I am tagging you since I tried, but could not send in the crash report. If you are not the most appropriate person to notify then please pass this onto the right person.