I see that others are mostly having trouble unlocking audio log achievements in ODST. I only have one that won't unlock, Gumshoe. (Find the 3rd clue unraveling the mystery). I really hope all of these "Done! Unlocking..." issues are fixed soon. I plan on getting all of the achievements (25 left), and it would suck to not be able to get 100% over this one achievement that won't unlock, when it clearly says it's 100% completed.
Halo 3 ODST 3rd clue achievement won't unlock!