Need some insight... (dual pcb problems)

Ok, so I have here a Hori Tekken 5 PS2 stick modded with Sanwa parts, and an '09 Madcatz 4716 (late) 360 pcb. Following several guides listed here and on other forums, I have (for the most part) succeeded in getting this to work.

Lately I’m noticing that joystick input will just drop, randomly. For instance, I played for a few hours last night on my friends 360 and it worked fine. A while later, I couldn’t move… It was like the joystick wasn’t even hooked up. This is also occurring when I use the stick on the PS2. All buttons will still work flawlessly at any press.

I’ve used my multimeter to check for continuity everywhere, and it’s all correct. My soldered contact points on the 360 pcb are clean and tight, and the same goes for the hori pcb which the wire is actually inserted through and soldered at the bottom. I’ve added the appropriate +5v (360) to +3.3v (PS2) wire and a common ground to common ground wire between both pcbs. As far as I can tell, I’ve done everything correctly, including daisy-chaining all the grounds on the joystick and button side of the terminal strip.

Any gurus have any idea why my joystick dies randomly? It’s a Sanwa JLF if that matters, not even a year old.

Thanks.