Apple has acknowledged an issue with "pink squares or pixels" on displays connected to new M1 ARM-based Mac mini computers. According to the available data, the causes of this problem are currently being searched for. Most probably it is hardware issue with M1 chip.

Cases of pink pixels and squares appearing on displays connected to Mac mini have been known for a long time. Since the launch of the new M1-based Mac mini in November, there have been numerous reports of such cases. The exact cause of pink pixels on displays is still unknown to wide public, but Apple know it. Based on user reports, the problem occurs when HDMI is used to connect the display rather than Thunderbolt. HDMI controller has lot of problems on M1 chip, including color modes restriction and such bugs.

There was no specific timeframe or even any promise for fix, but Apple's message appeared a few days after the release of macOS Big Sur 11.2.1, which does not seem to solve the mentioned problem. It is possible that a fix will be prepared for the launch of macOS Big Sur 11.3, which is in beta testing since February 2.

Apple recommends to put your Mac mini into sleep mode, wait two minutes, and then return your computer to work.

Yes, they are serious.