what would make my suburban go into 4 wheel drive on it's own? on 2005 Chevrolet Suburban 1500

On about three occasions my suburban went into auto 4 wheel drive on its own; however, I was able to go back to 2 wheel drive without a problem. Then one time it went into 4 wheel drive on its own, I could not get it out of 4 wheel drive until I shut the truck off. Could this be the control module for the 4 wheel drive?

I had a similar issue around 118K miles; infrequent at first then eventually stuck in 4WD. It was diagnosed as transfer case encoder motor which I had replaced. No problems since.