Once Steve and Barbara get married, whenever Dodie is talking to them, they refer to each other as mother or father.

I think this is weird. Do you?

Steve to Barbara "Mother, Dodie is talking to you". "Oh, thank you father. Yes, Dodie, what do you want"?

Steve and Barbara are talking to Dodie in her room. Steve: "What do you think about that, mama?" (I think he used the "mama" name near the end of the first episode of season 11.)

Yeah, I never thought about this, but it is out of the ordinary. Speaking to your spouse, and addressing her by the name your child would use.