Mike surprises Gloria and Edith by shaving his mustache in this episode. But his mustache was conspicuously absent in the episode prior to this one (The Boarder Patrol (1977)) and no one mentions it.
When Archie and Edith are in the kitchen after Archie initially fails to notice his chair missing from the living room, a shadow of the boom mic can be seen on the refrigerator behind Archie as he's sitting at the kitchen table.