A parking lock is built to stop a car rolling in, not to withstand a car driving through it. A slow bump from a bumper is normally fine, but a heavy impact can bend the arm or loosen the base plate. That is why we fix the plate to a solid floor with proper anchors and fit an arm strong enough for the bay.
If an arm has been hit, stop using it and have the arm and the anchors checked. Qasar Al Neil Automatic Doors repairs and replaces arms and refixes loose base plates.