Okay, the notchy feeling, depending on "which one" :c), is the magnets going past the armature core of the stator, and is, when turning the motor rotor slowly, felt as resistance, then push, then resistance again that is consistent in its degrees...
I was flying the Mini 4 Pro at 0 deg.C and up in the fog cloud this weekend. It came back with water droplets on the body and ice on the propellers. No lens fogging and no battery problem.