there isn't a day without Manuscript crashing, even multiple times a day. It crashes most notably while copying and pasting, while saving, while undoing and while deleting a corrupted paragraph (how do these corrupted paragraphs ever appear?).
Manuscripts crashes every day
Mine crashes often enough that I've abandoned using it and gone back to Word. I ended up wasting too much time restarting it and redoing things, when I have a research proposal deadline approaching.
For me, it frequently hangs and requires a force quite or outright crashes when copy/cut and pasting, using the undo feature, or importing references from Papers3.