I did the ODST achivement , just at it says kill a guy while your airborne usong a man cannon , well i got it , and now it says i didnt , thus sucks -Yoink-
It happened to a couple of my friends, So your not alone! This will also mean there will be a fix for it.
Luckily it didn’t happen to me.
Well , i hope they fix it , its a diffucult one