Reoccurring flashing screen issue on 2 different new phones now

Just upgraded to the 16e at T-Mobile last Monday and started having a short burst of lightly flickering screen ( like a small flash for 2-3 seconds) and at very random. So after two trips to T-Mobile it kept happening and last night I went through an exchange and an ordeal but finally have another 16e…. And it’s happening again.

I’m starting to feel crazy because the guy told me he had never even seen this problem.

Does anyone know anything at all about this with either this model or other iPhones and would you have any advice for what this might be, as I need to pretty soon figure out if I’m going to switch to another model.

Thank you in advance