Intermittent resolutions and refresh rates on MacBook Pro 16

MBP16 w/ 5500m on Big Sur 11.1.

I am getting very inconsistent behaviour when plugging and unplugging the dock when using the display #1 DisplayPort connection. I have 2 LG 27UK650 displays. If I only connect 1(either monitor) to display 2 over DisplayPort it will come up at 4K60. The second displayport will seemingly randomly be 1080p/60 and 4K30. If I use the HDMI output on display 1 it sometimes comes up at 4K60, most of the time at 1080p60 or 4K30

I thought it might be a cable issue so I went and purchased 2 6ft VESA certified DP cables and the issue still happens.

After further research this appears to be an issue with macOS 11.1


Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

As you’ve found, indeed we believe this to be a problem with Big Sur 11.1. We recommend submitting feedback to Apple, the more users reporting these regressions, the sooner we can expect to seem them fixed:

See here for additional examples of others who are reporting the same kind of problems with other displays and devices:

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

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