The Facts of Life

The show went less believable in season 5 when they all started living together for forced reasons away from the school. But Mrs. Garrett running a baked goods store was at least plausible.
This episode, however, just took the show into Ridiculousville, as this new store was not just an eyesore, but a desperate attempt to appeal to 80s trends, which it did horribly.
This was where the show said in no uncertain terms that the days of Mrs. Garrett were over. She was a recurring character this season despite the primary set being her own store. Charlotte Rae was only continuing the show for the sake of the girls who wanted to keep going. She leaves at the end of this season, but only after assuring the show could continue with someone replacing her.

The show went downhill with season 5 leaving the school. But this, right here, is where the show just stopped being watchable.

Mrs. Garrett was missing from the majority of the back half of season six. This was the start of her "recurring character" status despite being in the credits. They'd essentially run out of stories for her, and even Charlotte Rae said the character had become boring. 

The times she does appear in the back half of the season, including this episode, are only in episodes that were actually recorded during the first half and aired out of order. This episode was recorded as the 12th for the season, but aired as the season finale. (Some context in the episode also gives this away.)