it is the notchy feeling but on this motor it more noticeable, it spins freely Slightly Stiffer than the others . Maybe I'm just paranoid had a crash last week don't want another one. It really nothing to switch out the motor if need be
Notchy is generally Ok. Differences in magnets and other manufacturing process vary as does this notchy-ness.
The best test is resultant heat from flight. After landing test motor temps. They should all be about the same.
This can be done by just feeling each as they should NEVER be hot enough to burn skin as the plastic [shell] would melt first.