validation casing for mixed tip use for 8 channels

api/src/opentrons/protocol_engine/state/tips.py

@@ -267,6 +267,11 @@ def _validate_tip_cluster(
             elif all(wells[well] == TipRackWellState.USED for well in tip_cluster):
                 return None
             else:
+                # In the case of an 8ch pipette where a column has mixed state tips we may simply progress to the next column in our search
+                if len(nozzle_map.full_instrument_map_store) == 8:
+                    return None
+
+                # In the case of a 96ch we can attempt to index in by singular rows and columns assuming that indexed direction is safe
                 # The tip cluster list is ordered: Each row from a column in order by columns
                 tip_cluster_final_column = []
                 for i in range(active_rows):