Happy to hear that
We always add 1-2 tick delay for next attack - So depending on your server tickrate, this may take some time (but i don't believe that 15min is correct?).
You should see the planned HERO_ACTION for your hero, which u can compare to it's arrival time. E.g. my Hero arrives with plunder on 19:21 and the next action is planned 19:22 (on server with tick 1minute).
This is currently not configureable and was not planned to be.