I have 4 applications enabled in Accessibility (Tasker, LastPass, Greenigy & Yatse Notification Plugin), but except for LastPass (which I only activated a week ago, after the problems started to occur) I've used them for a long time.
The kernel that I'm using is the original CM11 one, without any custom settings.
The UI is just crashing, without any messages. I have the same settings (no navbar, status bar hacks, no themes) since forever.
I thought that there is a RAM problem as the restarts seemed to appear when there were lots of apps running, or trying to edit a long G+ message. I also wiped the system a week ago and restored only a few system apps via Titanium Backup 126.96.36.199 (SMSes, witdgets, call log, data usage, blootooth pairings, stuff like that), but without much success.
I don't know what other information could I add...