RIFE transcoding above 4.12 doesn't work

Hi, I'm using RIFE to transcode to 48FPS, however, for some unknown reason every model above 4.12 just doesn't work. It transcoding, but not doing anything, when I check the GPU it doesn't put any load on the GPU at all, but every other model below or equal to 4.12 does put a load and I do see improvements. Can anybody suggest why? Do I need to do something special to allow the use of models above 4.12? Thanks!