I've managed to reproduce a bug I kept running into, which causes an assertion failure and then a crash.
I have 2 panes open (let's say, left and right).
My "active" pane is the left one (my cursor is there).
The file that's visible in the *right* pane (not my active pane) is changed by some external editor.
The next time I move back to the changed file, Sublime correctly notices that it was changed outside and offers to reload it.
When I click "reload", Sublime shows an assertion error, then crashes.
Happened to me for a while before I figured out the exact steps to reproduce.