Electrical problem with T5 stick

I have 3 T5 sticks. The PCB on one of them went out so I figured, what the hell, I’ll turn it into a Dreamcast stick. I hacked a standard Sega DC pad and soldered the stick and buttons to the pad. Everything works great, but when I hit triangle on the joystick (wired to “y” on the pad) it works fine. However, when I hit it at the same time as another button (air dashing or tagging out in MvC2) the other button’s command comes out and not the appropriate dash or tag.

I thought it was a bad switch so I swapped the buttons. It fixed it for a bit, but then it went back to doing the same thing! If I “shake” it around a bit, it will work properly for a while then fuck up again.

Any ideas?

check to see if there any wires touching or soldering bridges…