Touch bar not responding to touch

Hi, I have a 2019 16" MacBook Pro (MacBookPro16,1). It was sent to an official Apple partner because Bluetooth wasn't working. They replaced the logic board and the Touch ID module. After I got it back, the touch bar didn't respond to touch anymore. It displays and updates content just fine but there's absolutely no reaction to touch.

I'm currently running the macOS Big Sur release candidate. I also installed Catalina in parallel (fresh install, nothing restored from backups) to see if it works there but it doesn't make any difference.

What I also tried:

• SMC reset
• PRAM reset
• safe mode
• diagnostics mode (hold 'd' during boot) -> everything seems to be alright

None of those things made any difference and I was pretty sure the connection was just broken on a hardware level until the touch bar started responding to touch for just 2-3 seconds after logging in at one point. I didn't manage to reproduce this but there might be a slim chance that it's not a hardware issue.

Is there anything more I could try before returning it again? I had to wait two months for the repair last time and I'd like to prevent this if possible :/