I just tried it. I took off the case, stood the phone up on the table, held it in place with one finger on the top, and tired to unlock it.
It worked fine.
It took a couple of tries because the angle was wrong, but it worked.
All I'm saying is that if you were right, we would be hearing some people say it works with one case and not with another. Or we would be hearing about thinner cases that worked for more people. We aren't hearing that. Some phones work with all cases, and some don't work with any. Clearly there's an issue, but this one doesn't seem to make sense based on what we are seeing.
As I stated later on in my post, after I realized you got a non defective phone, you got a good one. Others were not that lucky.