What I've found is that face (cheek) slicing is most of the time and issue of skin tension.
And many times that tugging is not a dull edge, but a lack of tension.
If it's not a tension issue then a face slice is often from changing direction at a pause in the stroke.

Glad that you are getting a handle on the stropping - it is yet another muscle memory/habit that comes with a little practice.

And you have your mind right...as they say...but remember it is supposed to be relaxing and Zen like...don't start beating yourself up "Like a Rented Mule" as one of co-workers used to say...

Good luck and good shaving...