A while ago, I was making wooden tabletop clips and needed to crosscut multiple short pieces to identical lengths. Marking individual cutlines would have taken too much time, so I decided to set up a stopblock on my power mitersaw. Unfortunately, at the end of the cut, the saw would jettison (and often ruin) the freed piece, which had been trapped between the blade and the stopblock.
After a bit of head scratching, I realized that the fix is to set up the cut with a removable spacer between the stopblock and the end of the workpiece. Hold the workpiece firmly against the fence and stopblock while removing the spacer. Now the sawn piece has room to fall freely away from the blade at the end of the cut. To further minimize the chance of kickback, allow the blade to stop fully before raising it out of the cut.