Played around with MF and AF+MF with the EF-M 22 f/2 and was likewise disappointed with its implementation. This camera will be used strictly AF only with EF-M lenses. Loved the IQ of the EF-M 22 -- fantastic little lens. Still haven't quite figured out a good way of holding it with the right hand and still have good access to the controls, but it's a good trade for the compact size.
Did you try switching to back button AF? That enables full time manual focus with the 22mm (when you have AF+MF selected) in the menu.
I was trying to set to BB AF (custom function 5), but it didn't seem to be working the way i thought it should. There might have been something else that I had set that might have over-rode it or locked it out. I'll have to dig into the manual to see... Thanks for the heads up!