I'm not really sure what is the issue here but I'll just try to describe it as I see it.

I've stumbled upon a recording: https://musicbrainz.org/recording/3a770151-716f-49e8-8fba-8df8516ea8ad

that has incorrect character in recording name (ąwiat where it should be świat).

The same name is returned from API (in Picard).

However, when I wanted to edit the entry to correct it... in edit box it's displayed correct: