Apple Studio Monitor and using Green Screen

[BrightEyes]

Anyone having trouble getting green screen to work with virtual backgrounds when using Apple Studio Monitor?  My virtual backgrounds kind of work without my green screen, but I get the halo effect.  Any suggestions for enabling green screen? I check the box, but all I see is a green background - not my virtual background.  Running 14"MBP in clamshell mode. Have updated Zoom for M1, and updated firmware on Monitor