Unexpected behavior w/ 2 identical BenQ BL3201PH monitors connected via DisplayPort on a GTX 980ti, running 10.13.6. App is only able to control DDC on one of the two monitors. When the working monitor is the primary "Mac" monitor as chose in Display Preferences in the Arrangement tab.

Disabling the primary monitor in MonitorControl settings does not fix this issue. When I disable the "main" working monitor in Monitor Control preferences, adjusting the other monitor brightness causes the main monitor brightness to then change. Same applies for the brightness sliders in menubar. Has anyone else experienced this?

I've tried changing the system monitor names with no luck, no change in name in the MonitorControl app. Will keep trying other options.