Dogs are spawning in the nether or over-world, inside the obsidian blocks and dying when going through a portal.

Plugins installed: Leashable, UnbreakableLeashes, MyDog
Optifine: Better Dogs (texture pack)

Disallowing dogs to teleport via the portal, and instead teleport on you when you change dimension and they're not sitting, seems like the easiest fix. Alternatively is there any decent portal plugins if changing the portal is a workaround?