It’s an all or nothing achievement. You must clear all the propaganda posters within a 24 hour period. It will remain at 0% until the entire achievement is met, then it will go to 100%. If any poster is missed, or time elapses on any of the posters the achievement will not complete.
Note: I believe that the timer is tied to the daily reset, not a true 24 hour time limit. So if the reset happens while you’re working on the achievement, you’ll need to start over.
From what I remember when I completed this achievement, I believe Dufly’s map is no longer accurate. It has 41 posters marked on it, but one of the marked areas did not have a poster at that location (or there was one but it was already torn down as you showed in your screenshot). I had to find the missing poster manually by running around the entire area with my button held down to display interactive items to find the missing one that was not marked on that map.
I’ll run through the area again and compare my torn posters with the marks on Dulfy’s Map to see if I can remember the spot where I found the unmarked poster.
edit
Well, I’ve been running around the area for quite a while now, even dodged a run in with a Champion Separatist blocking an area where I think it might have been at, and I cannot find a poster that is not marked on the Dulfy map. Though I did find several that are back up again and are not ‘torn down’ any longer, so I screencapped a few of them, though there were actually like 5 that are back up. I probably am just remembering it wrong as it was quite a long while ago. I suppose the only course of action would be to go to each and every one in order again after they reset to make sure you get all of them. :\ I wish I could redo the achievement on an alt.
