[BLOCKING LIVE CONTENT] Additional sound files in RP do not play.

Verification builds: 1.7.0.2 - R7 Beta 21 Build 1117901

Summary:

In Stranded in Space, Mutant Battle Arena and more, I have added dozens of additional sound files using sound_definitions. None of these sounds play. However edited versions of existing vanilla sounds do play.

Impact:

Being able to add custom sounds to our games is obviously of paramount importance. Some creators use voiced dialogue as their main way to convey information about the world to the player. This severely impacts their ability to do so.

Repro Steps:

1. Download and create Stranded in Space
2. Press the button to test the dialogue

Observed Results:

This triggers a command that has /playsound sis17 @a in it. It triggers correctly however there is no sound. You can also verify this by using the command yourself.

Testing the same thing with local files results in the sound being played. What seems to be interesting though is that edited vanilla sound names, do still work correctly. So it seems to be specifically with additional sound files.

Expected Results:

 A female voice should play saying "Constructing"

Screenshots/Videos attached:

Regression Build: 1.6.0.8