Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.
Generally speaking flickering is not a sign of a bad dock, but it can indicate some updates may be required (especially on the Windows PC side). For macOS, no updates should be required for the computer itself, so we may need to look into updating the firmware on the dock.
To get a better idea of what’s happening, since the dock has two HDMI ports, does it matter which HDMI port on the back of the dock is used for the monitor(s) that’s flickering? Or does it appear that the flickering occurs with either HDMI port, regardless of monitor model used?
There’s “Display 1” and “Display 2” for the HDMI (and DP ports):
Please don’t hesitate to let us know of other questions.
Thanks again for contacting Plugable support and best wishes!
Senior Engineer | Product Owner