Known Existence: October 1, 2002
When you finish the solen matriarch's quest to kill infiltrators and become a part of her colony, her workers, queens, and warriors will no longer attack you. However, they will still attack your pets on sight. This can cause problems, since killing enough solen from the hive you are friended to will cancel your friended status to the colony.
Solution: Only take mounted pets into the colony to prevent them from being attacked by the solen.