Probably a miss load, if it has edge numbers. Been there done that frequently.
When you attach film to take up spool hold film by thumb on film at sprocket tooth and wind the rewind knob carefully to tension film in the cassette until you detect resistance.
Then close back then check the rewind knob turns as you shoot the blank frames.
If it does not turn immediately you have a miss load.
If you get a bottom loader Leica, Zorki or Fed you will get lots of miss loads.