I couldn't find another post about this, apologies if a duplicate. I've seen this often in GF, bugged listings persist for hours or even days, if you try to join you get "Application error: the listing owner is busy" and it becomes Delisted, but when you refresh it's back. I've seen it with Archive and Trials, the same trial listing showing the same amount of people in group, days later.
For example both of these Archive listings, you can see the error and "delisted" but they come back on refresh.