This is a fresh install on a brand new 7a; my SO has not even had this phone a week. If the phone is in his pocket and moving around, there is no full screen notification of the incoming call or any way to answer it, EVEN IF you quickly enter a PIN to open the phone and go to the stock phone app. It's just ringing away and no info appears on the app until the 4th ring timeout, similar to this post from last year: https://discuss.grapheneos.org/d/15305-my-phone-rings-but-the-call-does-not-show
I've checked the full-screen setting as advised in that post, and it's already set. Do not disturb is also inactive. I've reproduced this bug 6 times this morning, and after two restarts.
Interestingly, the phone correctly displays the full screen (answerable) notification if the phone is sitting stationary on a flat surface (it literally cannot even be sitting on an incline, it must be FLAT), just not if it's in a pocket or in hand, moving about. Can anyone help me understand what's going on here?