DerFennek, Thank you for posting in the Intel® Communities Support.
In order for us to provide the most accurate assistance on this matter, we just wanted to confirm a few details about your system:
Is this a new Intel® NUC?
When did you purchase it?
What is the model of your monitor?
Were you able to use a higher resolution on this specific device before?
If yes, when did the issue start?
Did you make any recent hardware/software changes that might cause this issue?
Does the problem happen at home or in the work environment?
Please attach the SSU report so we can verify further details about the components in your platform, check all the options in the report including the one that says "3rd party software logs":
Any questions, please let me know.
Intel Customer Support Technician
You probably need a Firmware Update to fix Compatibility and Performance Issues on the Cable Matters product. Converter Cables contain chips that can be flashed when the product is plugged.
Which product are you using?