iPhone 8 keeps restarting when home button connected

Hi guys, I have an iPhone 8 here. Problem: the phone keeps restarting. I opened the phone, there is no sign of water damage. Here are what I tried so far:

1. Put a known good battery, same result.
2. Restored the phone to original factory settings, same result.
3. Tried a new screen, same result.

Then I connected the screen without the home button, the restarting stopped, and the phone works normally. I inspected the home button flex, no sign of cut or damage. In fact, when home button connected, both click and fingerprint work perfectly fine, the home button doesn’t get hot, just normal temperature, but the problem is phone keeps restarting with home button connected.

Any help would be highly appreciated. Thanks.