Adam p

I have a 2015 gmc 1500 4x4 on the floor, and it started to sift into 4 wheel on it owe well I’m driving down the rd , the leaver doesn’t move still says it in 2 wheel but you can tell the transfer case is in 4 wheel, I pull the leaver into 4 and back to 2 wheel drive and it goes back to 2 wheel then after a few minutes of driving back into 4 wheel drive, has anyone seen this before!!! Thanks