Thanks for confirming the issue, @jdot. It certainly shouldn’t be happening.
I have a new white case on the way. I’ll expose it to the same conditions (as far as I’m able to replicate them) and see if makes any difference. I presume you don’t have one to test it to see if helps.
As mentioned, if the white case helps, I’ll keep the phone. If not, I’m afraid it’s the death knell.