Group posting/commenting with nickname feature - Doesn’t seem to be working?

Does anyone know if this feature was turned off? All of a sudden I can’t comment on posts within groups (any groups I am in) unless it’s my full name, the nickname feature isn’t working, I select it and it says I have already participated with my actual name (I haven’t). It is letting me create new posts within groups the nickname though, but I have to change it first, it used to be set as default to my nickname…