I'm also running on thumb (All the time - I don't update to new CSSU-T, until new version of thumb appears. Not that it should matter for this particular case, but telling full picture, anyway).

As for testing systemlock package, doing it now, one device with -devel, and will install stock on another one, tommorow. By stock, you mean full CSSU thumb, with just that package downgraded to stock, yep?

Anyway, I'm also inclined it is not related to tklock - all locking things seems to be "solution", instead of problem cause. + the fact that no one reported it before latest CSSU update (although, -devel isn't widely used on everyday devices, obviously, so random nature of this bug could prevent it from being detected).

Either way, due to - again - random nature of this bug, testing will take some time, and only answer I'll be able to give, is a) It happened (for sure), or b) I *think* it doesn't happen anymore (or I just was lucky to not run into it).

/Estel