typefilter not being applied to URLs on sort

Hi all!

I've been using ZenCart for a long time now and I've had this issue as long as I can remember. Going back several years. I have assumed this whole time that it was some rogue code on my part. With the 2.1.0 upgrade, I decided to meticulously replace my files and recreate my template from scratch based off of the responsive template. When that didn't fix these particular issues, I decided to finally figure out what was going on and now I have found the issue, but I am unsure on how to fix it.

When using the music_genre sidebox (just an easy way to call the genre), it takes me to a list of all my products within that genre as expected. It even Filters by category as expected.
However, when changing the Sort By, it always brings up a full list of products, not narrowed by the genre, despite showing the genre in at the top of the page. Upon further inspection, the Sort By is not adding "&typefilter=music_genre" to the URL. If I manually add that to the URL, all the filters are respected, including the Sort By. This is also an issue with the record_company sidebox/filter.

I've been scouring the files all day and can't seem to glean where the disconnect is. Thank you and I appreciate any guidance.

Site: https://selectohits.com
Zen: 2.1.0
PHP: 8.1.31
Plugins: as far as I can tell, this happens with no plugins, but it could be rogue code on my part.