Since the problem in March, I have upped the minimum frequency to 192mHz. For the longest while I haven't had any issues.
But since I installed my new Anker battery (was on a half-in-the-bag EZO Power 1900mAh), the problem came back, happened twice now, a week apart.
I'm trialing KitKatDS right now, but will probably go back in a week or less due to wakelock (Android OS) issues. Judging by above, when I do I will bump up the minimum even higher. Hard to see the correlation with how the battery will be causing it, but I see no other change.
Primary Phone: HTC MyTouch 4G Slide (Doubleshot), S-Off, running CyanogenMod 10.1
Backup Phone: Samsung Infuse 4G (i997R) running Beanstalk 4.4+
On Order: LG Optimus F3Q, running stock