On my current map I am in an area that was not spawning any wolves. Playing peaceful mode. Lots of other animals and villagers, but no wolves. Traveled all the way across the map, actually just a little off map, in order to get to a biom with the spruce trees and wolves around. I tamed a wolf and started back towards home. I got in a boat, traveling relatively quickly and expecting him to follow. My dog was in follow mode. After about a minute, dog disappears and is gone. There was no danger, aside from the fact that he was swimming. So I thought the boat may have caused the glitch. I tamed a second dog, made sure he was in follow mode, and wandered around slowly a few minutes to make sure he was sticking with me. Then start heading home, running but not using boat. Double check to make sure he could telephoto to me, he followed me fine for about half a map. Then just disappears. Again, no danger, I was in a flat area with no giant holes or dangers. Just gone. I wandered around area a bit hoping he might teleport, no luck. Went back home and neither dog has showed up after a couple game days.