I have a teleporting machine (star trek style) with command blocks on my server that can teleport people a couple hundred blocks away. when I have a wolf or a cat following me to the teleporter and I teleport away 8/10 times the wolf won't come with me.

This issue is also present with boats. When you're in a boat and float on the sea in a straight line for 10 minutes while a wolf is following you it won't allways teleport to you once you reach land.