https://collider.com/the-golden-girls-biggest-plot-hole/

'The Golden Girls' is one of TV's most beloved sitcoms, but that doesn't mean it was perfect.

This is the explanation:
These plot holes are largely due to the fact that this was before every network sitcom had a “Show Bible” to keep track of details. There are multiple writers throughout the series, and it is unclear how often they communicated with each other. Even though most of the writing was fantastic, perhaps there were too many cooks in the kitchen. It was also before the advent of streaming services and binge-watching, which make it easier for fans to catch mistakes like these. Yet even with these mistakes, it hasn’t seemed to dampen fans’ devotion for the show.


This was common with many TV shows back in the '80s and even the '90s.
It is clear that the writers didn't feel a need to remember all the details because they figured that the viewers wouldn't remember them either.