I opened a bug recently about frequent crashes, and it was promptly hijacked :-) So here's a backtrace. I am seeing frequent crashes. Often (like this one), I work for a while, then keep the app open for some minutes, then when I resume working, Impress crashes after a few mouse clicks. In this case it was "Insert Slide" from the Slide Sorter view. Running on Ubuntu latest.
Created attachment 44582 [details] gdb crash backtrace
Created attachment 44671 [details] Another backtrace, this time no user interaction at crash time
*** This bug has been marked as a duplicate of bug 37850 ***