The Real Thing: Part 2 - S4-E2
Continuity mistake: In the previous episode Jennifer sees Ellen Reed for the first time while talking to Alex (when Alex is holding Andy). In this episode, she sees Alex viewing picture of Ellen and asks "who is Ellen Reed?" as if she had never seen her before. (00:12:10)
Answer: A scene very similar to the one described happened on the show Mr. Belvedere that was on in the same time frame as when Family Ties was on. Perhaps this is what you are remembering.
af4dable ★