I was watching a YT clip from 2000 of Maureen surprising then interviewing Susan near the old Brady stage at Paramount, and at about 1:20 in this video, there is a BB clip of Marcia applying freckles to Cindy's face in the girls' bedroom, with Cindy complaining "Ow! Freckles aren't supposed to hurt! That's enough!", and I don't have any recollection of this scene or in which episode it appeared. I was guessing "Jan, the Only Child", as the video has a still from that episode, but I don't think that's right. I'd love to know, as I think I missed something. I'm pretty sure it's from Season 3 if not later:

https://www.youtube.com/watch?v=qhFk2OzSK6U&t=189s

Jan, the Only Child at about 9m30s.

Jan, the Only Child at about 9m30s.

OK, thanks! It's probably been cut out of the show now, even on Me-TV.