I would video the behavior and talk to your vet about it. It could be a weird personality quirk, but it could also be a sign that something medical is going on, like gastrointestinal pain or any number of other things. A vet will have the training and knowledge to be better able to identify if something is wrong, and I always find that it's important to trust my gut when it comes to my animals behaving in an 'off' way, even if it seems small and silly.
It's against forum rules to offer medical advice to prevent anyone getting incorrect, dangerous advice that hurts their dog, so ruling out medical problems with the vet is your best first step.