Just a simple thought here... Only because I have done this before... Did you put the correct water volumes into Bru'n Water?
I did check and foun a discrepancy but ran it through Brew'n water and it only moved the PH down .02
I did mix the chemicals together and store them in aluminum foil over night.
I mixed the mash additions less Pickling lime
pickling lime in a seperate foil pouch
Boil additions in another foil pouch
Could the Chemicals started reacting to one another and/or the foil and changed in a way that would alter their effect on the mash?
I have Zero chemistry knowledge so may be it a foolish question but it occurred to ask since im trying to get to the bottom of this.