having also an error once profile setting page is visited. and guest users can view the categories and recent page but they can't access any post. even if i already checked the access and read in category settings in ACP.
I figured it out from going through the code. I guess hidden groups are deliberately not populated in userGroups. Seems like it'd be helpful to have an extra flag for groups that determines whether or not it's selectable as a title aside from hidden (maybe I don't want the group or list of members to be available publicly but still want to use the associated title) but it might be too much of a corner case for me. For now, I've unhidden the groups that I really needed and made sure to disable join requests on them.
Yeah it might make more sense to use slugs instead of the actual group name when storing the key. Right now when you go to the group page you use a slug in the url and then the code grabs the group name using that slug to load the correct group's data.