I have a M1 Mac Mini. I have my main screen attached to the HDMI port. (No problems)
My second screen connected to the USB-C port, flickers out every 2minutes for about a second and then returns. I have changed cable and connectors. Monitor is a HDMI connection. Using the Apple AV adapter to covert USB-C to HDMI. Any ideas. It is very annoying.
Mac mini 2018 or later
What I was suggesting. was to TEST the ACER on the USB-C port using the Apple USB-C to HDMI adapter and the Z-Edge on the HDMI port.
Also if you are using any of the thin poorly shield HDMI cables that came with either of those monitors?
Then you need to replace them with better quality Premium Certified HDMI cables.
What brand and model are your displays?
I would try switching them around to see if the flickering follows the display or stay with the USB-C connection.
The main HDMI monitor is an ACER with an HDMI input only. If I just use that one everything is stable. It's when I plug the cable in for the second monitor. It is a Z edge 17 inch. It connects fine. But after about two minutes cycles to black for about 2 seconds and then is stable for another two minutes, and then it does it again, and so on. It also affects the main monitor. Switching monitors does not seem to change it. Do you mean instead of converting the signal coming out of the USB-C to HDMI, to get a thunderbolt monitor and eliminate the C to HDMI converter? The converter is the Apple C to HDMI (AV) connector. BTW this really started to happen after the Big Sur upgrade. I upgraded to 11.4. Thanks for the info. It was helpful.
Hope this additional information helps.
I have the exact same problem and it's driving me mad! Have you managed to fit it?
No solutions yet. I will try an upgrade cables, but most are already high quality.
M1 Mini and flickering screen
