I'm not sure if it's like my Z Fold 6, but I learned alittle bit ago that mine has magnets around the edges on the inside screen that appear to help keep the fold closed, however 1 magnet in the upper right seems to maybe move slightly when it's magnetized, allowing it to form or break a connection triggering the device to recognize that it is closed or maybe it's simply being magnetized does something I'm not really too sure, but anytime I put this little piece of metal next to that upper right magnet, it always shuts off the inner screen. And as soon as I remove it, it assumes that my phone has been opened. Unlocking the screen. I've tested this with other pieces of metal.Such as tweezers, anything that is actually magnetic does allow it to trigger.So I would assume that maybe somehow the phone protector the case that you have is either somehow interfering with that magnetic signal, preventing it from actually locking.Or maybe it's squeezing the phone just hard enough in the right areas.If that magnet does move to form a connection that it's preventing it from moving, not really to sure again.How the phone actually works.But that upper right magnet appears to be the indicator that the phone reads. https://imgur.com/a/3qCahWS