Macs do not support Multi-Stream Transport (MST), which prevents from using a single DisplayPort or USB-C port to daisy-chain multiple external monitors in an extended display mode. So the the virtual multiple display modes are not working correctly on Mac.

Our application is trying to read all resolutions of an external monitor. We have observed that, for the external monitor there is a mismatch in resolution list in our application and the resolution list in system settings. We are using the apple API "CGDisplayCopyAllDisplayModes" to read the resolutions.