The sounds are corrupted with the dispenser who shoot arrows and they collide

I wanted to test with a dispenser to put arrows trying to kill drowneds (to know why) and a moment when there was no more arrow, the sound of the arrows that was with the collision did not stop doing the same noise all the time, I looked everywhere to see if there were no arrows, no arrow, I looked below the dispenser, no arrow. In my opinion, the sounds when the dispenser projects arrows and collide are repeated even if there is no arrow on the horizon.