Car Doctor: An SUV’s turn signal is constantly on the blink

Q. I have a 2025 Cadillac Lyriq with 2,500 miles and a chronic problem with the left turn signal. The signal will intermittently fail. I got an error message to check the taillight bulb. I’ve had the car to the dealer twice. The first time they rebooted the software with no success. They then replaced the taillight assembly, and this corrected the problem for about a month. The second time the taillight failed I brought the car in for service and the service manager saw the taillight was not working. However, when they restarted the car to bring it into the service bay the taillight was working fine. GM stated that this is not a known issue, and there are no recalls. If I turn the car off and let it sit for a while the problem does resolve itself. This is becoming a major concern and anno