Hello icoriona33
After reading your issue, yes there is a manufacturing defect with many iPhone X's . I myself bought an iPhone X 256GB Space Grey and I had this very bad issue.
Apple Knows about this but they haven't addressed it with any official message. I have sent them evidence.
The Apple Support will deny that there is anything wrong with the device right from the L1 level to the Senior level.
But trust me I have sent the information to the Engineering Team, they have validated the claims, they last said that they are working on it. But it seems to me that they are not going to do anything to address the current iPhone X's affected but use the information to remove the issue from the next iPhone model.
I managed to get my iPhone X replaced after 3 months of back and fourth emails,calls which is not the way Apple should have gone about addressing as their Diagnostic Software wasn't able to pick up the defect.
But after getting y new iPhone X it is better but still has the issue. So till now I haven't heard any update regarding the issue.
But this is the best information I can provide you.