I have a horse that stocks up on a regular basis all four feet and bad, but never any heat. He just doesn't like to move! He could be in the largest pasture and stand in one spot. But every day I would come to the barn, he would be stocked up, I walked him out or rode and he'd be fine again. But the next day it would be just as bad.
I've always been told it doesn't hurt them and just means a slower warm up. I would only be concerned honestly if it DIDN'T go away with exercise or if it had heat.
Funny enough, he is pigeon toed so I started him on a joint supplement to help out his pigeon toed leg. It was just straight MSM and ever since he's been on it regularly he is rarely if ever stocked up (in fact for a year I forgot about how bad he would get stocked up!) I didn't know if it was related or not, but a month ago I had to take him off the joint because BOTH tack stores were out and he started stocking up again right on schedule and just as bad as before. Never heard of joint medicine suggested for stocking up before that though.
Take a ride across the badlands
Feel that freedom on your face - Breathe in all that open space
You'll understand why God made -Those fly over states