Does this use a bootloader? I know it changes which it boots based on the slider being open. But how does it determine where the target kernel is? Maybe it's loading from the wrong place?

Another possability (more likely actually):

I know there's a "fail-safe" in the original Titan kernel that causes it to not load the "default" settings if you reboot the device in quick succession, or if the "last boot reason" flag is watchdog. I think that's still in. Maybe that triggered, and it was "stuttery and slow" because it was using the old default kernel rates? (600 / std voltage?)