Man, that hurts to hear because you clearly put the work in and it just got wrecked by a temp you didn't know about. I've had the same thing happen and it's such a letdown when you pull the foil back and the bark is just gone, all that nice crust sitting in a puddle of juice. My pit runs hot too, usually around 270 to 285, so I feel your pain. For me the wrap is the real killer, I cut mine way down to like 45 minutes to an hour and it made a huge difference. You still get that tender pull but the meat doesn't turn into shredded beef. Don't beat yourself up, next time you'll know your pit lies to you and you can plan around it.