TES+ square button not working properly

so, I need to buy a better stick.
the only one I could find around here in the used market is a TES+ (the Shadaloo branded) and the price is fine.
only thing, the guy says the square button works, but not all the times, like if you press it 3 times it could work 3, 2, or 1. he also says that the thing is still covered by warranty and the shop is in the city so I could just ask them to repair the stick (or give me a refurbished one maybe).

I’ll try the stick before eventually buying it, but what could it be? I mean, would I have to just change a switch, a button, or would I risk to bump into something more serious/expensive/complicated?

thanks for your help

The PS4 sticks by MadCatz are notorious for having fucked up PCB’s. If that’s the reason and it’s not a defective button / wiring, then avoid.

I won’t take the risk then :frowning:
Thank you