That really sucks Butlerg, sorry for recommending them to you in the other thread. But I wonder if you have issues with your other mounts. Judging by the condition of the stock mount you took out, I would bet that you have other mounts that need replacing. Maybe that put more stress than normal on the SLS. Still, it should have been designed to hold up to that kind of stress, even if the other mounts are shot.
I'm going to take mine off and take it to work to use some magnifying equipment and look for cracks. I really like the SLS, but not if there is a chance that it will fail like that. At least if the stock mount fails, it's designed well enough that it will still hold together.