Default Won't wake up sometimes?

Lately, I've noticed that my Note 3 won't wake up from a sleeping screen, but it doesn't happen all the time, and I cannot pinpoint what's causing it. If I remove the S-Pen, sometimes it will wake, but not always. I can tell the system is running, because the S-Pen audible notification sounds are working when I remove the pen, or put it back, etc.

If I long press the power, but not long enough to force shut down, sometimes it will wake, but not always. It's so random, that I cannot figure out the cause. It's fine for days, then it happens 5 times in a row, then it's fine again.

Anyone else seen this?

I'm thinking of a reset, but I'd like to ask for suggestions first, because it's a PITA to set up everything again, even with backups, and I might reintroduce the problem, if I restore the cause.
PHONE: Samsung Galaxy Note 3 (SM-N900)
ROM: [KitKat][4.4.2] Stock N900UBUDND1 APR 17, 2014 CF-Auto-Root

TABLET: Kindle Fire HD 8.9 Stock

STATUS: Flashing Addict!

“He who answers a matter before he hears it, It is folly and shame to him.” Proverbs 18:13