AWD problem??

2016 570sp. The atv says AWD but I noticed coming out of a mud hole this weekend my front left tire wasn’t spinning. And yes I did have it on 4×4. I even clicked over to the down hill 4×4. Is there a problem? Do all 4 tires not move at the same time? I’m still new to polaris and this atv has 72 miles on it right now.