This is a solution to the "glitch" that was keeping me from getting this achievement. I was getting the headless zombie glitch and could not complete the mother superior "sepulcro" cemetery mission and could not advance in the game on the 360 game of the year disc version. I tried saving the game to the cloud and downloading it on the Xbox one to see if this would correct it which did not work. This is what worked for me,
1. from the dashboard go to settings find your red dead redemption game save files. I took my latest save and made a copy on the 360 hard drive.
2. then I disconnected from the Internet (personally I prefer a wired connection so I just unplugged my cord).
3. Then I cleared my cache. I think you press y when under settings.
4. Load game and play. If you want to earn the achievement while online wait till you finish the cemetery to "connect to Xbox live" you will see it save in corner when the cemetery is cleared.
5. I then took the update and it restarted the game, now I'm back "online" and I went back to the town and completed the requirements (short cutscenes) for the achievement. And achievement popped and same old glitchy gameplay resumed.
I assume if you're stuck in the game in other spots the same thing will work. I was able to play most of the areas even with glitchy gameplay (or just do the storyline offline).
From everything I could find online and in videos it appears that the glitch is caused by the update and clearing the cache is what clears the update.
I also noticed that my challenges that should've carried over from the main story were not available when playing with the update installed but when the update was gone I had access to tomahawk and explosive rifle challenges. I plan on uninstalling again and getting those challenges complete I'll add an update if this works.