Combat music brush entity does not work(msarea_music_dynamic)

Combat music brush entity does not work for me (msarea_music_dynamic). The global/worldspawn key+value pair also does not work for me. It may set the data somewhere, but it will never play idle or combat music. msarea_music_dynamic will function as a music player, but the intended purpose of setting dynamic music did not work for me.

It should be noted that the addparam/MSscript method of doing combat music works. The way you do it is play music normally, as you would with a msarea_music brush entity. That is your idle music track, and you can use the addparam key+value pair to set individualized mob combat music. (e.g. on a boss monster "params/set_cbm;thebirth.mp3;set_cbml;3:27")

TL;DR
The MSscript dynamic music system works, and the brush entity and/or worldspawn methods do not.

Wiki reference from patchnotes:
https://msrebirth.net/Developer-Knowledge-Articles/Archived-MSC-Patchnotes/2015_FEBa/?h=music#mapper-toys

Start with the linked patchnotes section, then search the codebase for msarea_music_dynamic and the worldspawn music key/value handling. Reproduce the issue with a map using the brush and worldspawn methods, comparing them with the working MSscript addparam method. Done means both intended dynamic music methods play idle and combat tracks.