Tireless Feat (as found on Raider and I think Kensei and some others too) is bugged.

It said your Stamina will be drained at a lower rate, which I interpreted to mean "spend less stamina"; it doesn't.

Two ZA still drains me (make sure you ZA one after another immediately) even with Tireless. One ZA is supposed to be exactly 50%, since if I even with just a second or so between them, I will not be exhausted after two ZA (since I would have recovered "some" stamina during the wait). So Tireless basically does nothing?