Bug: Volume set in volume mixer does not save

[ertup0]

Describe the bug

Custom volume set in Windows volume mixer gets reset to max volume after relaunching the game.
Tested in Momentum Mod, Portal Revolution, P2CE
This does not happen in regular P2 or any other Source engine games (I did not test cs go though)

To Reproduce

1. Launch any Strata Source game
2. Change application volume in volume mixer
3. Quit and launch the game again
4. Volume gets reset to max

Issue Map

N/A

Expected Behavior

Application should save changed volume

Operating System

Windows 10