Bizare. Trust Ducati!
As you have allready replaced the rod and its failed again I cant help thinking that something is up with the clutch or the thrust bearing.
Does the lever feel ok, is it particulary heavy, tthe clutch should be quite lighti f a bit wooden feeling. Does it have the full travel is it coming right back to the bar with no resistance?
I thin it woud be a good idea to strip the clutch down and check the pressure plate is not binding and the bearing is ok and twisting the rod.
Strange one this.
Kev