Your frequency has been higher and you haven't had enough recovery for your grip. But in any case you were overdoing it so definitely "curb your enthusiasm". But don't just abandon it. I do NOT want to here you crying about needing straps for deadlifts a month or two from now.
You can't lighen your weight to do GHR's. Therefore it's not wise to do 2 more sets for form. You could have thrown in a set or two in the other lower for that.
Can't you stack up more of those steppers for the box squats? They were better though