I have a player sync issue... anyone else?

I am using two instances of Squeezelite and using LMS to sync them.
When I change volume on one, it changes on the other in the web interface, but not on the actual output.

I know this worked in the past... it did not work for me in 8.2.1 and I just tried 8.4.0 and it still seems broken.
I don't know what version it last worked in.

Is anyone else seeing this?
Am I doing something wrong?

Please help.