Premiere Proxy proxy workflow resulting in random files

So I imported all of my files and proceeded with the normal workflow of creating proxies. Everything seems fine and normal, but upon reviewing my timeline with all the clips every so often premiere/media encoder decided that instead of creating a 720p proxy it would instead create a 4k file from the original UHD. All the files were proxied in one go, so no settings would have changed on individual files from it being setup in premiere and sent to media encoder. Anyone else have this happen? This is a new one for me.