It is ridiculous that Samsung still won't fix this minor issue. From my research it affects many models, maybe even current 2022 models!
The Soundbar (HW-Q80R) auto switches to "Game Mode Pro" sound mode when it sees the TV (Q900RB) in "Game Mode" picture mode. That's fine, what is not okay is the soundbar stays on "Game Pro" sound mode indefinitely until it is manually changed back to the previous sound mode, (in my case "Standard").
Samsung TVs switches back it's picture mode, why not the soundbars too!
Game console is used > TV switches to game mode > Soundbar switches to game mode > Done playing the game console > TV reverts back to saved picture mode > Soundbar retains "Game Mode Pro" sound mode > All content watched on TV sound is on Game Mode Pro" sound mode indefinitely. > Have to manually switch back soundbar sound mode to standard.
Game console is used again and it switched back to "game mode pro" sound mode and the cycle continues!
Only a firmware update will fix this.