Yes they are also not listed on my Groups.io account. I'm not sure what the names were -- only that they began with an 'N.' They were groups I hadn't visited in a long time. I don't remember the names. Just that there were a couple of groups listed between the two Northeastern groups -- one of which begins with 'NE' and the other 'No' -- and they're not there now.? But if there is no notification when an owner deletes a group that would explain it.
I haven't joined any groups since I migrated to Groups.io from YG! -- other than Beta and GMF -- so the missing groups go back to the Yahoo era. In fact, there's several others that gradually died but I still belong to. Once in a great while I click on their message list but there's usually almost nothing to see.
For the future, I have taken a screen cap so I have a record of my groups.
tommy0421
Tommy Meehan