On both my S2 and S3, I have recently noticed that when I have deleted a show out of a group, I have gotten the window that says the Group is no longer needed because I deleted the last remaining show. However, the Group still was needed and it had other shows remaining in the group. The group wasn't actually deleted.
As I have only seen this happen recently, I suspect it may be a bug caused by the recent Winter Update, but I did not see it listed in the 8.1 bug list thread posted here. Has any one else seen this problem?