So there's some threads I just shouldn't read ...
After coming across this today my phone has started turning off by itself (doing routine things, like pressing the "Read" button on an SMS). There's gotta be a weird coincidence there (I had an underclock issue where the screen wouldn't come on a couple months ago while earlier that day I was reading the post on how to replace a bad LCD panel - so I get to overreact like that).
I think my issue is more about battery as I have been tracking it the past several hours (three shutdowns in a row at 60% battery, and then one ten minutes ago at 20%) but it continues to work itself out (with some weird stuff like notification panel crashing on me on one of the last reboots).
I have what I presume is a cheap 1900mAh battery (EZOPower) that is starting to show it's wrinkles. I have dropped the max processor speed a notch according to a recommendation in this post:
...hopefully that was the issue. I nandroid'd my device just in case something goes wrong. If it continues, I'll swap batteries and see.
I'm hesitant to shell out for a couple Ankers because I currently have my eye on the LG Optimus F3Q (although getting one would be three months away, I gotta have priorities).