KDE Plasma5 - Cannot change default program for mp3 to MPV

Hi all,
When I am trying to change the default program for MP3 files to be opened with MPV (https://mpv.io/ ) the Plasma5 changes it back to Dragon Player. Doing so for other media types works just fine. Here is a video for you to see what’s happening:

https://db.tt/Nu2CJXGL

Thanks.

Right click on the mp3 and choose ‘Open With’ and then ‘Other’ (at the bottom).

Look under ‘Known Applications’ and select ‘Multimedia’ and scroll down to MPV Media Player - highlight it.

Put a dot in ‘Remember application association for all files of type…’ and click Ok.

Let the system configuration update and done.

strange… it worked the way i showed in the video for all file types and applications…