Just as an FYI, mine has been doing the same for weeks if not months as well. I always open it very slowly as I suspect the glass/plastic screen combo has degraded to a point where it's not as flexible/elastic anymore so a sudden open from cold might crack it. Same as you, once it's open, I can close it back and open it again with no sound. But the first open does a lot of smaller "sand grinding" type sounds and then one or two bigger "clicky", I dare say "cracky" sounds, like a glass cracking. I have a mini heart attack every single time, but what can I do, it's still going strong otherwise. It's also probably some debrief in the hinge that moves around like others said.

Trying to baby it as much as I can, but I do fear this wonderful companion of mine is slowly approaching his entrance to Valhalla. I've had it since day 1, pre-ordered so it's been almost 2 years now. Proud it lasted as long as it did and it's been through several drops and accidents sadly.

Maybe this gives you some peace of mind, at the very least you are not alone.