K from QK MMA B-partition has GMEM iter at mode 1, NOT mode 2. (None,0,None,0) hardcodes mode 1 to 0 → TMA always loads tile 0. (None,None,0,0) keeps mode 1 free → correct multi-tile loading. Proof: diag n=256 went from cos 0.711 → 0.999999 with this one change.