Tamed Wolves don't teleport while following you.

I recently found and tamed three Wolves, and while they seemed to teleport to me just fine while crossing a river, I wandered into an Extreme Hills biome and they seemed to stop following me for a time. They were all stood in place when I back-tracked to get them, and didn't move until I got close enough to them. It happens if you get a specific distance away, to the point where the Wolf should teleport.