Don't use a "every x seconds" trigger condition for this ; if the actual framerate is slower, or not a multiple, of your time, it's not guaranteed to run at regular intervals. It's not a flaw in the "every x seconds" block, it's just bad logic.
Use a timer you update every frame with dt to make sure events like that happen at a fixed frequency.
E.g in pseudo logic :
every tick >
timer -= dt
while (timer <= 0.0)
timer += interval
(this version ensures that if the frequency of the event is much higher than the actual framerate, the logic can run multiple times every frame ; this may or may not be desirable depending on the case ; change the "while" to an "if" depending on the requirement)