They usually just get loose on the butyl adhesive contact. Not likely to break unless someone has been there and intentionally done something wrong. Like said could be just resealed by warming up the butyl and pressing them back on firmly. Actually this can be done as a quick fix by just pulling the lower part of the door card and doing it from between, because the culprit is on the lower edge of the barrier.

__________________
E39 530dA -02 M-Sport Messing metallic
E53 X5 3.0dA -06 Sport Stratus grey
E70 X5 40d -12 M-Sport Space grey