animate guardian death in zone persists across different characters

I have two characters that both use Animate Guardian as a primary source of damage. If my animate guardian dies on one character, since it can no longer come back in that map, I switch to the other character to finish the map. However about half the time, when the other character enters the map I get the message "Cannot resummon an Animate Guardian in this area as one has already died" and that character's Animate Guardian ALSO disappears.