Even though many TV shows have continuity "bibles", there are still TV series which will ignore those "facts" in order to serve the needs of a script. And this continues to this day, even when the show-runners know fans have access to DVDs and streaming services to bring those discrepancies to light.
But these Zonks just need a televisiologist to splain them away.
"TAKE MY WIFE, PLEASE"
Helen Chappell mentioned that her first cello teacher was a woman.
"THE GIFT, PART ONE"
In this episode, we learned that Helen's first cello teacher was Winston Catlow.
This is very easy to splain.
Winston Catlow had a sex change.
If ever a Winnie Catlow shows up in some TV show, I'd say we've got our man.
So to speak.....