I'm at the end where you fight Salt Upon Wounds and Joshua Graham attacks me every time. I thought I might have accidentally sprayed him with SMG fire, but didn't. Every time I start the fight he's enemy. I also heard there's supposed to be a cutscene before the fight, but I don't get that. All I hear is Joshua yell "That's it!" and then he starts shooting everyone me included. I tried reloading an earlier save before you're in the Three Mary area and played through again, but with the same result. What's the deal?

I'd suggest reloading a save before the final part of the DLC (the part where you choose to fight or escape). If something has gone wrong once you get into the final then reloading a previous save within the final might not help (if I understand you correctly, if I'm wrong please correct me).

Hope this helps.

I'll try that. I reloaded a save before you go into that canyon with Joshua, but not farther back than that.

That worked. I just reloaded right before I talked to Daniel. Thanks!