I'm also having this issue.
Cursor gets stuck, though characters typed still appear, key combos seem to be misbehaving (e.g. ctrl+shift+up/down, left/right, ctrl+shift+d)
Another key characteristic of this random bug is that selecting File > Exit in the menu has no effect whatsoever once this corrupted state is encountered.
I've noticed on Ubuntu 14.04 based Linux and Windows 10.
Sublime Text build 2221 and 3114 respectively.
Anyone have thought of a way to fix it? Or at least track down what causes it? It seems to happen so randomly, without anything in particular provoking it. And after it happened there is no other way than to