Those aluminum hold down straps are probably just weak. I had the same problem with the earlier "EZ" ARF kits from a few years ago. I broke several. They looked just like the ones in your pic. Get rid of that complete mount & replace it with a black composite mount. Drill the holes clear through the beams & use socket bolts, washers & lock nuts. Its also a lot lighter. Of course, you probably already know this, & if so, just ignore this post!

Barry