Malkom: What is your locale, and what are the translations for "Seethe" (http://www.wowhead.com/?spell=41520) and "Imp" (the warlock pet)? Those errors mean that there's no translation for those strings in the Babble library.
It seems the Hunter ability Mend Pet currently isn't handled, it appears to generate the same threat any healing spell would. (Testing with rank 1, which heals for 25/tick I needed 8 ticks to pull aggro when my pet had dealt 90 damage while in melee range, which is a very close margin to what I'd expect)
Should this not be generating threat? I'm confused.
Perhaps it IS generating Threat but not displaying any?! Don't have a hunter to test...
I guess after the /petattack from my voidwalker... but it could have been some different spell either... (Warlock lvl31 if that matters)