No timer on special guard call for Provincials?

Is it purposeful or a bug that a Provincial and Provost can call guard set after guard set after guard set, back to back to back to back. I fought and killed 6 sets guards within 15 ticks from a level 41 Provincial while raiding the Spire and it finally got so out of hand I had to leave. I get it, there has to be perks, but isn't this a bit out of hand? It made the raid simply impossible.