I have noticed that just about EVERY place that lists episodes of The Nanny lists 6 episodes AFTER The Finale, and those listed after include The Producers and The Dummy Twins (which, for obvious reasons, have to come before The Finale.)

https://en.wikipedia.org/wiki/List_of_The_Nanny_episodes#Season_6_.281998.E2.80.9399.29

Does anyone know what it was always like that?

Yes. CBS pulled The Nanny from its schedule in the middle of its final season due to poor ratings. CBS brought it back late in the season, and wanted the finale to air during May sweeps period, so there were some episodes left over that aired during the summer.

A similar thing happened to Happy Days in its last season.

Yes. CBS pulled The Nanny from its schedule in the middle of its final season due to poor ratings. CBS brought it back late in the season, and wanted the finale to air during May sweeps period, so there were some episodes left over that aired during the summer.

A similar thing happened to Happy Days in its last season.

So, the others were written first?

I was struck by how they totally changed Niles and CC's characters for Yetta's Letters, Maggie's Wedding, and The Baby Shower (both are totally love-addled and happy, and interact very little on screen but we're told they're in a relationship and it's definitely in its "honeymoon" phase.) In The Finale, they're together...but much more the Niles and CC of before they got together, character-wise.

If fans had seen The Finale and not any of the others, there would have been a LOT of speculation / fan fic about when the baby was conceived!

In the next-to-the-last-episode before The Finale, Fran and Niles meet Fran Drescher (!) and they talk about her show. She (Drescher) even says to watch the series finale the following week! So, whenever they filmed that episode, they must have intended the finale to come after.