Today, shortly after the 9PDT reset, the skills of all my cooldowns and of the purity generation resetted, which allowed me to use them again. This was quite helpful, as it awarded me with additional purity, but I doubt that its intended... so there might be a bug somewhere with the timers.
I didnt track it exactly, but the second reset seemed to happen roughly at 9:20 PDT, plusminus some minutes... after I used my trade-ability that is... so I could use it again.
I used my trade-ability roughly half an hour before the reset afair, so I could use it three times within an hour, but it should have only been possible twice.