Question [Q] Touch screen responsiveness fading after boot - Software or hardware?

I recently revived my TF101 from the dead after deciding the other day to buy a new charger - last time I used it, it had a slow charge issue which a new charger fixed perfectly! It's probably been off for ~1 year.

After turning it on, I noticed after a while that the responsiveness of the touch screen was awful - I flashed the latest version of KatKiss thinking it would fix it. Turns out this problem occurs even when in TWPR Recovery, but I want to be sure that it's a hardware issue before going through the hassle of replacing the digitizer. I would be awful to replace it and still have the same issue

Exact symptoms:
  • When the tablet is first powered on, touch screen works as intended.
  • As time goes on, the tablet becomes less and less responsive, eventually reaching the point where no touch is registered!

Advice on this would be greatly appreciated - is this a software (kernal?) issue or do I need to get a new digitizer?

EDIT: Just figured out it was because I was using it while it was charging - apparently this makes a difference! I feel a bit silly