I am not sure if this has been addressed before, but I rolled a monk with decent STR (yes, CON and AGI are higher but that's not the focus for my question). I was going to be using Qtr staff the whole time, but only to find out that the game doesn't recognize the staff as a 2h weapon, or at least when the feats Forstalling Strength (+1 AC when weilding 2h Weapon) and Follow Up Strike (bonus action when you attack with a 2h weapon using 1d4 + STR mod for dmg) are concerned. I am not sure if it's a bug or working as intended. The only way I can get my AC to increase for Forstalling Strength is to wield a crossbow.
Those feats look for the "two-handed" or "heavy" tags, which staffs do not have. Staffs are "versatile".
It's not a bug, just plain old ufairness. Versatile weapons don't have much support, while heavy and finesse weapons do.
Typos happen. More so on the phone.