There have been reports that M1 Mac mini users are seeing weird pink squares appearing on their external displays when it is paired with the computer. It is unclear as to what could be the cause of the problem and it seems to have started back in November 2020, which is roughly around the same time the computers were launched.
According to users, this problem seems to be happen more when users connect their displays over HDMI compared to Thunderbolt, but it doesn’t mean that Thunderbolt has no issues, it’s just less. MacRumors has managed to get their hands on an internal memo from Apple which states that the company is looking into the problem.
There is no word on when an update will be issued that will fix the problem, and hopefully it’s a software problem instead of a hardware one. If you’re experiencing this problem on your M1 Mac mini, Apple has suggested putting the computer to sleep, waiting two minutes before waking it up, and then unplugging and replugging the display to see if it solves the problem.