I cannot begin to tell you guys how happy I am to have found this thread. I have this same issue on my 2013 335xi, I've blown out the inner cv joint 3 times on the passenger side (always that side) on my car so far. I just replaced it again. I've been working to figure out root cause of this.
Here is my thread
https://f30.bimmerpost.com/forums/sh...light=blow+out
This last time, which was about 2 weeks ago, I had the support bracket, which attaches to the diff, break as well and when I went to change it there were 3 of the 4 bolts very loose so I'm thinking that this also may have been the cause this time since that failure would let the axle on the diff side move up and down.
All 3 times the shaft with the tripod bearing on the end is out of the receiver on the diff side. i've talked to a guy who will make me a custom longer axle shaft which I believe may help me long term since I want my car lowered.
These are some of my facts and thoughts:
1) Axle length - at a normal car height the length of the axle shaft with the tripod bearings is such that it sits in the stock position in the receiver at the diff with a full range of movement in and out allowed
a) lowering the car increases the length between the wheel hub and the diff which moves the end of the axle tripod closer to the edge of the receiver which will limit how much movement it can tolerate without a bearing going far enough out to fail
2) Excessive movement of the engine - due to motor mount or motor mount bracket, as you mentioned and I didn't think of, which again makes this distance between the wheel hub and receiver longer
3) Excessive camber as I found illustrated on a Kies Motorsport You tube vid where Brian caused a failure by increasing camber with a mod using F80 control arms on his f30 xDrive. This would also increase the length as above.
So anyway there appears to be a small tolerance for the allowed length between the wheel hub and the receiver that takes the tripod bearing end.
I will be changing my motor mounts this weekend and will inspect my motor mount brackets as well. I have a guy who will make me a custom length axle shaft but I have more measurements and investigation to do before pulling that trigger.