Just updated to 10.0.50 and came across this issue myself… 2nd speaker selection no longer working. I wish I had seen this thread before updating. I do hope a hotfix will be coming soon to address it.
Late to the party, but I just wasted an hour trying to get this to work before finding this thread.
Seems when you configure “speaker2” then “speaker1” gets set to “unused”. What fun. Trying to get my 3 monitor pairs and my headphone feed working. This is basic functionality (that works in Cubase) and should never have gotten past QA.