There's not much about either iteration of Lr that I don't know.
I used it for years right up and thru Windows 10 Pro.
I now use them on a new iMac and MacBook Air. (10.13.2)
Lr Classic Ver 7.1 and Lr CC Ver 1.1 + the Mobile app.
That said: I haven't a clue what your post is for. We are not mind readers.
This is a Computer problem.
You will find other post similar to your but in the end it comes down to problems with your hardware.
If you don't switch between LR, Perfectly Clear and PS and only have LR open does LR crash?
If you run that P C software or PSby itself do you have any problems?
The point of the post is to report a series of crashes that originate from within Lightroom code. ...and to determine if others are encountering similar. .. mind reading not required
I believe that the problem occurs as a result of running Edit In (Perfectly Clear) and returning control back to LR. The SEGV fault is likely a thread timing/interaction issue -- just a guess from a quick scan of the backtraces in the coredump. I do not think my hardware is causing the problem. Up until the more recent version of LR and Mac OS, I did not encounter these crashes. Note I will be in contact with Perfectly Clear support as well.