Rune of Adventure’s description says it gives 50% Endurance, Daredevil Elite Specialization increases your Max Endurance Threshold by 50, implying Daredevil has max of 150 so 50% of that is 75. But Rune of Adventure only refills 50 flat Endurance.
(I didn’t test it but I think this problem also exists with Weapon Sigils that give percentage based Endurance)