From a Reddit thread there’s another user who said that had screen record on when the glitch lines appeared but they didn’t show up in the video.
Would that say it is hardware or not necessarily?
I just found that thread and read it. It looks like his issue is different though, bc he was not unlocking his phone.
For the rest of us, the issue is solely when unlocking. There could be something else wrong with this phone.
I would suggest to stop worrying about it, or take it to the Apple Store. At any rate, if it is software it will be fixed by Apple, if it is hardware it will become increasingly worse and the issue would be unavoidable, and Apple would offer a replacement. You will not find the evidence you are looking for here or anywhere else, sadly, for the time being--but the issue will be solvable one way or another