[haus]

If it's not Flexmail, since it's a problem with 2 consecutive TPs, I'm going to agree that it's probably a software issue with something you've installed. (People that have gone through 8 TPs may disagree, but we'll just stick with the odds here, particularly since you said you have installed "many, many" apps - the more you install, the greater chance of problems like this). Have you installed any button managers (AE Button Plus, dredsensor, keyboard driver cab, etc.)? Any power control panel apps, like things that enable fast charging or tweak power/backlight settings? Any locking apps like Pocketshield, S2U2, sensorlock, devicelock, etc.? I'm not singling any of those apps out (I use some of them with great results), but there might be an incompatibility.