My wife’s 12 Pro Max has similar issues where certain apps don’t respond at times. We’ve seen it particularly with mail, camera, and phone. I was trying to listen to some voice mails yesterday and after playing the first one I couldn’t scroll down or up or select another voice mail. The only thing that responded was the play/pause button but it was very laggy. The phone has been in an Apple leather case and has had a glass screen protector since the moment I peeled the white screen sticker off. It did not feel warm at all when this happened and hadn’t been used for a while. I don’t think it’s an issue with the screen protector either since you can swipe up to get to the app selector and can close the unresponsive app and the whole screen responds during that time. When reopening the bad app it works for one task (like going to the next voice mail) and then stops again.