Default Subtitle Language Not Changing

[unotdead]

I downloaded a bulk of mkv files with multiple tracks and subtitles. I pulled aside 1 file to test before doing it for all of them.
The default audio and subtitles are in English. I changed the default audio track by just disabling all the other ones.
For the subtitles, I want to make Japanese subtitles the default (I am Japanese), while still having the option to switch to English.
I selected both options and changed the order weight of Japanese subtitles to 90, while keeping English subtitles at 100. I created the new MKV file, Japanese is set as subtitle track 1, and english is set as subtitle track 2, but it still defaults to the English subtitles as the first choice upon playing the MKV file.

Why? How do I make this not happen?

For reference, I am using MPV to play the files.

[Woodstock]

MakeMKV isn't intended for working on "downloaded files". It's intended for working with DISKS.