I have 48 Guest users spread across 14 teams; some of these Guests are part of more than one team, and these this setup has been running without issue for about six months.
I recently setup private channels in each of my teams and began adding relevant Guests, but some Guest members no longer appear in the directory listing when adding members. For example: Joe User (Guest) is a member of My Team, but when I attempt to add him to My Private Channel, I can see other members in the dropdown list (including other guests), but not Joe. This affects 6 guest members across private channels in three of my teams, and to be clear: all of my teams have private channels, and all of those private channels include a subset of all of my guest users.
And if that's not strange enough: Joe User (Guest) can be added successfully to *some* private channels, but not others, so the issue doesn't lie with a particular guest or a particular channel/team. I can't figure out a pattern. Has anyone ran into an issue like this? I'm well below any thresholds on channel limits or guest user limits, too.