Paewang/Datel PCB Diagonal Problem

I posted it in Q&A thread yesterday, but didn’t receive any answer so here is the separate thread if anyone knows how to fix it. This is a very weird problem, so bear with me.

I bought a Datel/Paewang a few months ago for intentions of modding it with a Myoungshin but didn’t really have the time. I modded it last night, everything works perfectly except the down/right diagonal. Right direction register, down direction registers but when pressed together no direction is registered either on my PS3 or PC. Even stranger thing is, when the stick is switched to X360 mode, all 9 directions registers without any problem (tested on PC).

This is the old Paewang pcb it seems, where the button-pcb was connected with a sort of wire harness to main pcb. I found a similar thread posted around 5 years ago, but no solutions or helpful replies there: Peculiar Problem (Paewang Mayflash Board)

Any ideas, @laugh ?

If it’s working in one mode but not the other,I would have to guess the pcb is bad.