Platform movement behavior issue

ok is a sidescrolling game, My character is like a police and the enemies are some bad guys, then when my character collide with an object the enemies start shooting. The animation of the enemies shooting is ok, you can see the movement of the guns firing but just one bullet come out.

Every X seconds or on specific frames should work. You aren't putting them as a sub-event to the collision are you? Collision is a triggered event so only occurs once and won't be repeatedly checked.

Hard to guess the problem without knowing your events.