1. http://forum.xitek.com/showthread.php?threadid=880398 (machine-translated English page here) and the picture showing the damage is as follows:-
(The above picture is posted at Post #32 in thread.)
It is told that his DAL lens was dropped to the mattress of his bed (for a short distance) where the user sat on and the plastic lens mount of his DAL lens was broken immediately!
2. Yet, there is another DAL user reported (in Post #74 of the above thread) that his lens mount was broken so suddenly without his attention for just using for several times for his new lens! The mount of his DAL55-300 lens was found broken just when he picked out his Pentax DSLR camera from his backpack with the lens mounted! Here is his posted picture showing the damage:-
It can be seen that the break is different from the first user's that the base of the plastic mount was broken. To be somehow different, the second DAL user had one of the three bayonet petals disintegrated into small pieces under normal use and without any dropping, he insisted. He has tried to contact dealer about this issue and asked for a replacement but of course he was denied. It is just because the user could not prove that there was no mis-handling by the user and the dealer firmly "believed" that it was just the user's own fault and that the Pentax gear would not be as vulnerable as that! :-|
After all these, the first OP decided to mod up his DAL lenses so as to improve the reliability of the mount, which is just so vulnerable in his eyes. Look! Here they are! Have you ever seen those DAL lenses in metal mount?! :-o
(Above: Modded DAL 18-55 in Metal Mount)
(Below: Modded DAL 55-300 in Metal Mount)
Wow, excellent job indeed! Bravo, guy! :-D