During the final mission, when you have to kill and resurrect your friends to defeat Joseph Seed, the sheriff died in a way that was out of the zone and I couldn't revive him. This is literally the objective of the fight. The only gimmick to the fight is revive your friends after you shot them and they couldn't be revived.
Steps to recreate:
1. Get into the final fight with Joseph.
2. Kill one of the revivalable characters near the zone edge of the map.
3. attempt to revive, character is now no longer an actionable person, and there fore, cannot be revived, making the mission impossible to complete.
I had to reload my last save which was all the way back at the lodge you blow up. Really frustrating. Look for video attached of bug.