Is there a way to know why Plex prefers the wrong metadata?

Until you Plex Dance that movie - nothing will change:

as far as Plex is concerned that movie never changed - and you can put it in as many different libraries as you want.

I am suggesting you name your files properly - that is a correct response.

You are suggesting anything and everything to avoid naming your files properly - that is a misguided response.

For clarity - I am never wrong suggesting using correct file names.
…and I feel fine…