I have a number of different OM bodies, as well as a number of different Canon EOS bodies. I use bulk film.
I've never tried a straight cut with the OM bodies. But my practice is that when I rewind my film I stop before the leader is fully inside the cassette, so that I can take off the end of the leader as a "mark" indicating that the film is exposed.
The narrow part of the leader strip I use with bulk film is much shorter (about 1 inch long) than the narrow part of the leader strip on factory loads.