iPhone 7 water damaged, when it never got into water, also the phone is Waterproof

Today I booked my iPhone 7 for repairs because it just stopped working. It was stuck on the boot loop.

I then received an email with a quote of R4880 for a swap for as the for was liquid damaged. My question is, how? The phone never got into water, and yes they might pull that "humidity and moisture card", but that is also impossible as the iPhone is ip69 certified water and dust proof so none of that is possible, and my iPhone is still under warranty as of the moment I booked it in.