I've been trying to re-unlock Mama Mush after the last BC reset. I finally got to her cub without a cookie, and I was even charged, but no Mush was unlocked. I made a ticket to make sure I wasn't mistaken in my thoughts that she should have been unlocked; I was instructed to make a post here.

I also didn't see a similar topic on the pages through which I looked, so I apologize if this is already a reported issue.

Yes - it was discovered that it's actually a chance event, not automatic. You can lock this topic, thanks for checking up on it!