According to the bulletin, radar detectors that are hard-wired behind the rearview mirror of certain 2020-2022 Corvette models can affect the flow of voltage elsewhere in the car. That can cause increased voltage to auto-dimming driver's side exterior mirrors, causing them to permanently dim and fill with a mess of squiggly lines. This can't be fixed, so once it happens the mirror needs to be replaced, per the bulletin.
The problem affects the "X1 connector" behind the rearview mirror, where a radar detector would generally be connected. The technical bulletin doesn't explain why this fault occurs, however.
2020 Chevrolet Corvette
The prescribed solution is to unplug the radar detector and replace the damaged exterior mirror—all outside the car's warranty coverage. GM doesn't cover damage caused by aftermarket devices.
The bulletin also specifically mentions radar detectors, but not other devices. Jalopnik points out that a dash cam could also use the same connector, but perhaps the built-in camera that's part of the available Performance Data Recorder system means it's less likely that owners will install aftermarket dash cams. It's also not surprising that owners would want to install radar detectors in a car as fast as the C8 Corvette.
The bulletin did not mention any potential hardware or software changes to address this issue, so it looks like Corvette owners will have to be careful about adding radar detectors for the time being.