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

[JuiceWSA]

Until you Plex Dance that movie - nothing will change:

The Plex Dance ™

The purpose of this is to remove all cached metadata and xml data for an item that Plex usually keeps. This helps when you want to “start from scratch” for particular item move all files for the media item out of the directory your Library is looking at, so Plex will not “see” it anymore scan the library library (to detect changes) empty trash clean bundles (in menu next to server name, when accessed under ‘More’) double check naming schema and move files back scan the library Support articl…

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…