Pets will follow a target OOR (out of range) and OOZ (out of zone). This is especially annoying, since you can't always recover a lost pet; eg. /pet heal <target>, target runs off, pet zips off after, never to be seen again.

Pets should not leave voice range and if they do manage to get OOR due to bad pathing, they should teleport to the owner. This would fix about 99% of the bad pathing on pets. They should never follow anyone but the owner into another zone.

Work-around: none, though you can make a /pet guard macro and quickly target yourself and hit it if your heal or kill target looks to be in danger of getting OOR.