Leica M6 winding mechanism

Hi everyone, I have a question for the Leica M6 winding. I’ve noticed that the film advance lever on the Leica M6 feels different when winding it back compared to a M4 or M2. It seems like there’s some sort of slight grinding sensation with the M6. Has anyone else experienced this, or is this normal for the M6? Thanks in advance for your input!