Bug Report: Variation uses the incorrect instrumentals unless accessed from the chart editor

[Chidubemmo]

Issue Checklist

• I have read the pinned Issues Guide
• I have checked the Issues/Discussions pages to see if my issue has already been reported
• I have properly named my issue

Platform

Itch.io (Downloadable Build) - Windows

Browser

None

Version

0.5.3

Description (include any images, videos, errors, or crash logs)

I have attached a video below, sorry for low quality, I had to lower the resolution but the audio is still intact

2025-02-03.17-39-07.online-video-cutter.com.1.mp4

As you can see the instrumentals are the one from normal ugh, and only uses the correct one in the chart editor.
If you are asking, the file isn't missing from the directory as seen below.

Also, I tried opening from the terminal (start Funkin.exe) but I can't seem to find anything telling me that it has problems finding the file.
I haven't checked the source but, if it can help, it doesn't seem to mention the instrumentals getting cached only the vocals.
This also isn't an ugh specific thing, I just used it as example because it's the track with the most different instrumentals at the start.

Steps to Reproduce

1. Have a variation, possibly for a custom character, of any song
2. Open it from freeplay
3. It will be playing the default track
4. Open the chart editor and set it to the variation
5. The song now uses the correct inst