I have been following this post with great interest and have some food for thought.
Maybe this has been over looked maybe not (have not seen it discussed anywhere so far) but one thing I see different between the BDS front upper mount and Mark's 3" front mount is the third bolt on the outside of the strut mount. It seems like more brushing failures are with Mark's 3”, which do not utilize that extra outside bolt. As Jason stated there is a lot of side load as you go up in lift. Based on the failures my guess this side load is towards the inside. Now could having three bolts holding down the mount counter act that side load somewhat? I am no Mech Eng but I am thinking that only having two bolts would not limit the possible movement in the y plane as the strut travels. X would be front to back of TB, y is side to side and Z would be up/down. Without the third bolt, maybe there is just enough movement over time to cause this type of failure. In addition, does Mark’s front mount have the sleeve between the bushings? It kind looks like it does from his picture on his site but since I have not seen them first hand it is hard to tell. Mark needs to send me a prototype lift with a third bolt for testing for the benefit of the community.
Edit: I could be off in orbit with this.
Mikekey when you installed your BDS did you use that bolt? I would think so but just asking because I have not see any picture of it in any post. BTW, a few pictures in your build thread are missing or broken link...