Quick Mute is not muting in the KSC buildings except VAB, SPH and Tracking Station

Quick Mute is not muting the sound in the KSC buildings except VAB, SPH and Tracking Station.
Pressing F6 shows the icon mute/unmute even though it is not working.
Game Version 1.6.1
Repeatable: Every time. same result with a clean Install
No errors logged:
[LOG 16:12:41.903] QuickMute(QStockToolbar)[1.31]: QStock.Refresh
[LOG 16:12:41.903] QuickMute[1.31]: Refresh
[LOG 16:12:41.903] QuickMute[1.31]: Mute
[LOG 16:12:42.046] QuickMute(QStockToolbar)[1.31]: QStock.Refresh
[LOG 16:12:42.046] QuickMute[1.31]: Refresh
[LOG 16:12:42.046] QuickMute[1.31]: Mute
[LOG 16:12:46.208] QuickMute[1.31]: Wait