Transfer Case problems of the 2014 Chevrolet Suburban

After returning from a trip and when pulling into a parking lot the transfer case shifted from 2 wheel drive into 4 wheel low on its own. No error lights came on. The indicator light did not reflect the change into low gear. The typical clunk of the transfer case shifting and difficulty turning on dry pavement were very evident. The transfer case was set to 2 wheel drive, not auto. After the car sat in the lot for app. 20 minutes, we backed up and pulled forward and the transfer case switched back into 2 wheel drive, again on its own. This happened one time so far.