Allan Tépper at ProVideoCoalition on ProRes in iPhone 13 turns out to be Variable Frame Rate

Allen Tépper at PVC has this article on tests by Carolina Bonnelly that show that the ProRes shot by the iPhone 13 are in fact variable frame rate and not constant frame rate.

This is so disappointing as to really use this footage you will need to decompress it to a constant frame rate. especially disappointing since the footage already takes up much more space and need to re compress it to really use it properly to get it constant frame rate. And you will be losing a generation in compression (I know ProRes can handle it better than HEVC but still).