Are the dumbbells in your living room, still? If not, your mother bought your membership and you should have had scenes with Aunt Cassie in her watermelon coloured outfit.
Edit: If you have - then you'll see this:
View attachment 1894338
So, your mistake caused the issue. Did you go back to a previous save and replay that day to fix it?
Is it an issue that the developer didn't expect that players wouldn't finished the shift? yes. It's difficult for any developer to think about every possible thing a player will do to fuck up a playthrough and make sure it doesn't happen. And it's something that needs addressed. However, If players do what they should be doing - the issue never would pop up in the first place. Do I call that a bug? No.