So it wasn't "condition levers to the max"...
So it was not "conditions levers to the max" per se that was the critical step. It was the "condition levers to the max" unaccompanied by a prompt increase in power.
So "condition levers to the max" was proper or atleast acceptable for that time and place, it was simply that somehow the "condition levers to the max" did not trigger the usual and necessary accompanying action of "PF increases power".
Perhaps the shared duties were confusing since it appears the designations of PF and NFP are not really proper for this particular flight. If there would usually be a sharp line of demarcation but this crew had blurred that line due to a recognition of PF having inadequate Time In Type then perhaps the "mentally associated" Prompt-Increase-In-Power was somewhat muted.
So it would be Exhaustion coupled with an adoption of an Ad-hoc Cockpit Resources Management blending of the PF and NFP roles?