Premiere Rush unable to import jpeg files

I am trying to import still images into Premiere Rush on my iPad Air (2020). I have confirmed they are all the same file types (.jpeg). But it completely randomly decides it does not want to import some of them (unsupported file type). All photos taken with my Sony a7III.

I have found on one previous thread that Rush does not accept still images that have more resolution than 4K. For example, it successfully imported a jpeg file with dimensions 3337x5005 pixels which is nearly double than the 4K resolution is. I tried importing a batch of 27 photos and only 6 were successful.

Exactly the same deal on my iPhone 13 Pro. Latest software and latest Rush version on both.