Issue using custom resourcepack sounds using /playsound

[PizzaThatCodes]

/viaversion dump Output

https://dump.viaversion.com/13f8046420aef9850fd3ef0e420a6223a3081279c6f8dbabb9dbc0ade8735704

Console Error

Put the mclo.gs link or text here.

Bug Description

If the server is 1.20.4, when you try to connect a 1.8.9 client onto it and try the /playsound announcer.welcome (using the TKR welcome for an example) it won't work, the sound works fine in singleplayer and if the client is 1.20.4 it works fine using the same resource pack on the server.

Steps to Reproduce

1. Login with a 1.8.9 client on a 1.20.4 server.
2. Turn on the Hypixel TKR resource pack (could be found here: https://hypixel.net/threads/tkr-assets-resource-packs-and-maps.1856344/).
3. Try to play a custom sound (for example, announcer.welcome, announcer.ready, announcer.go).

Expected Behavior

Sound should be played to the 1.8.9 client (since they have the resource pack enabled)

Additional Server Info

I have a proxy with no via plugins added just a TAB, Luckperms, litebans. The server is running the newest versions of all Via plugins (ViaVersions, Rewind, Backward).

Checklist

• Via plugins are only running on EITHER the backend servers (e.g. Paper) OR the proxy (e.g. Velocity), not on both.
• I have included a ViaVersion dump.
• If applicable, I have included a paste (not a screenshot) of the error.
• I have tried the latest build(s) from https://ci.viaversion.com/ and the issue still persists.
• I have looked at https://www.spigotmc.org/resources/viarewind-legacy-support.52924/ and it does not offer a fix for my problem

[Barvalg]

[FlorianMichael]

Please try if this is also happens on 1.9 clients

[PizzaThatCodes]

1.9 does work, seems to be just 1.8 where it does it.

[PizzaThatCodes]

Bump

[PizzaThatCodes]

Bump x2

[PizzaThatCodes]

Bump x3

[FlorianMichael]

Please don't spam bump messages, the issue will be closed / reacted to once someone is working on a fix