Most likely due to iruka being in the team. His mystery takes precedence over other mysteries due to his ability to interrupt. If no one was using mystery skills in the other team, then the other skills will trigger first. (this also includes iruka, who just randomly targets) When the first position attacks, this is most likely where the system would trigger the other skills. However, if for eg, WB Asuma was used, then the 40 chakra would allow both mysteries to be triggered without the delay I believe.

Just basing this off what I've experienced on how this game works.