Earlier today a group of us went to the Dark Lake to deal with the Troglodyte problem. We recieved the quest, and my journal updated. We fought through the trogs within, then killed the QA Boss, however, when we killed him no journals were updated, and it was then found that some of the party member's journals didn't include the quest in the first place.

To answer some common questions; The monster was not possessed by a DM. (We recieved the XP reward for killing him, as per usual.), he wasn't killed by a summons and there was some lag (At least on my end).

Hopefully that's enough information for you to work with.