User blog comment:Smartboy201/Destroying Biohazard Piles-Glitch (Spoilers for The Last Agent DLC)/@comment-4694083-20150221105336

I never had any problems with the burning of the posters. This achievement, however, has stopped me from getting my 100% completion rating and it makes me soo angry. -.- I managed to burn 39/40. Imagine my frustration. The only fix seems to be to delete the game, the data, and start fresh over from level 1. Start up the game and play the DLC start to finish in one setting. I think that was the last workable fix that I had read on the steam community pages anyways.

The Last Agent is also the worst of the four DLC's by a landslide, so I hate having to even load that baby up and play it again.