I have a 2016 MPB had the same issue with the external monitor when I was using a 3rd party dongle (which was half the price of Apple's dongles). I have now bou

I have a 2016 MPB had the same issue with the external monitor when I was using a 3rd party dongle (which was half the price of Apple's dongles). I have now bought Apple's dongle and no issues with the monitor.