I have had a good look at the parts diagram and yes, the mount that broke has 2 holes, not 3. I looked at the right side one and thought it was 3. Its very muddy up here right now, so it can be hard to see clearly until I get back to look at things later. I can not really explain how the mount broke off, but I think when the right stabilizr broke, and allowed the blade to move far enough left to let the left stabilizer hit the tire chains which broke the mount. It is very strange to me because I did not feel when this broke. The first time I broke a stabilizer, I knew the moment that happened. I believe they are sacrificial parts so they are doing exactly what they are supposed to do by failing under heavy shock.