Auto-Mute Mode not getting disabled with Line Out profile
It seems like the current card profiles only disable Auto-Mute Mode when using the "speakers" path, however, many modern motherboards don't have a separate speaker output - they just have line out, which is used for speakers when in a 2.0 configuration. This means that when connecting speakers to line out and headphones to front panel, the Auto-Mute Mode knob remains Enabled, and the speakers are muted.
One known affected motherboard is the MSI X470 Gaming Plus Max.