Having a weird issue with graphical glitching and wondering if folks have seen behavior like this before. The glitching *seems* to happen on all layers (sprite, bg, text), so I'm not sure where to even start. What's weird is that it doesn't happen during the demonstration but does during gameplay.
I cut the power traces to the Vinput pins on the EEPROMS and left them lowered, originally, but I've gone back and lifted all of them just in case (no change). I've reflowed all pins on the EEPROMs (no change). I've tried using both the original U15 PLD and Fluffy's hacked one (no change).
At this point I'm kind of baffled and wondering if it might just be the EEPROMs themselves, since they're Macronix branded ones I got off aliexpress, but I'm not entirely sure how I would prove that out.
Anyway, here's a video showing the issue, make sure to watch full screen, set to 1080p, and pay close attention to the sprites.
edit: I've gone back and re-ran the 3.3v power from my regulator--I originally ran the wire underneath the legs of the EEPROMs to keep everything neat, but on the off-chance that was interfering, I went back and ran it as short as possible. I should also say that when I burnt everything, I went through the same process of erase, blank check, write, and verify, so that shouldn't be an issue. I've also tested by taking the GFX board and swapping it into another known working cart and the issue followed.