I could feel my lower back rounding, it wasn't so much on the pull itself but more when I was putting it down. It actually felt painful, not the 'crap this is heavy' painful but more like I felt I wouldn't have been able to sit straight if I'd carried on.
I've already made mixed grip my friend

Made up for Wednesday's fail by hitting 5 reps 10lbs below my 1RM and discovering the beauty of leg drive in the bench, win some lose some!