Volume rockers don't work after swapping motherboard

Hey there. I’ve recently decided to replace the motherboard in my XZ premium. The old one was faulty, the details are irrevelant. I found a used phone on eBay, checked if everything works and swapped the motherboards. After turning the phones on I realized that the volume rockers are not working. I double checked every ribbon cable connection, everything looks fine. What’s interesting, after swapping the motherboards again the issue persisted. I’m sure none of the phones presented this issue before the dissasembly. Also, I was super cautious during the procedures. I’d appreciate any help.