could be a couple of things, 1 - the end has been damaged due to the non-even closing of the roof, or the roof has moved which will mis align the gas struts. Does your roof align correctly in the van, look even at the front and not overhanging? If this is ok then check the distance of each bracket against the rear hinge. If they are not equal, this could pop out the strut.
If all is good, we may be able to get you replacement end pieces, but can’t guarantee that this will fix the problem if something is mis aligned.
Cheers,
Ian