Here, I made a video of exactly what's happening. I made it to prove I wasn't crazy, but mataza beat me to the punch.
I just open and close the picture editor for simplicity's sake. I'm sure you don't want to watch me actually edit my sprites.
Anyway, here's the error text after the "pure virtual function call" error:
The exception unknown software exception (0x40000015) occurred in the application at location 0x0056ede.
The instruction at "0x00698901" referenced memory at "0x000021b0". The memory could not be "read".
The instruction at "0x7744dfe9" referenced memory at "0x00000008". The memory could not be "read". (This one came up twice)
The exception unknown software exception (0xc0150010) occurred in the application at location 0xc7943345.
After opening and closing the sprite editor 8 times, Construct crashes.
Holy crap, you're right. I can confirm this... I open the editor 8 times, then on the 9th try it crashes. Every time. That's weird, I never noticed it had any regularity to it before, I just thought it was an occasional thing.