Headlamp washing system cover explosive

Today I had a very special experience. After I confirmed the headlight wash system (because of Xenon) when I turned on the light, the one cover of the spray nozzle jumped explosively up and before I knew it, I drove over it with the car. I'm just wondering how a part of it can explode out of the bracket?
About two years ago, I had the front bumper repaired due to an accident. Could be here. something wrongly assembled, which only had an effect almost two years later? Ihc has to say that I had hardly operated the washing machine during this time with the lights on, but at least a few times without anything having happened.