F100 jamming with arista.edu

[Youngun]

I've been using arista 400 for a class for the first time and 5/6 rolls i've shot have jammed! It seems when the film first advances the tongue folds back for some reason, so when I try to rewind the motor cannot pull the film all the back, meaning when I open the back there's film across the body. I'm going to try cutting the tongue in different ways, but I can't figure out why this is happening. (i've shot with kodak, ilford, slide film, whatever and i've never had this happen ?)