9310B volume controller revokes speaker solo/mute status

System:

Windows 10, GLM software 5.2.1, 8340A x2, 9310B

Issue:

In the GLM software, when I right-click a speaker and choose solo or mute, it works as expected.

However, as soon as I adjust the volume using the 9310B controller, the solo/mute setting is cleared, and both speakers become active again.

What I want is for the solo or mute setting to remain in place, so that using the volume knob only adjusts the level of the currently active speaker.