Grease is grease? uh no
In 1972 I was a resident rep on the east coast for my company for the development of a control fin actuator for a missile. There was a very heavy load requirement on the output that had to be satisfied in the qualification test program. This was a small company with a very special responsible engineer who was very experienced and very intently focused on his design. Anyway, this actuator would not pass the test for satisfying that output load requirement. I don't remember how many times the company rebuilt the actuator to a new refined configuration and we repeated the test over a period of weeks. The test scenario was always the same, the tremendous load was applied to the output shaft simulating the air loads on the control fin in a high speed low altitude environment. We would see it start cycling from one extreme to the other looking good then well into the test period, smoke and sound was quickly followed by seizure meaning another failure. Then Don specified yet another kind of grease and after the rebuild we settled in for another test expecting yet another failure. It started out the same as always, looking good. It was getting near the failure point in the test period around 9 0'clock at night as I recall, and the monitoring went into hight intensity mode. It passed the previous endurance record and was still going, spirits started picking up with each second as it went further into unexplored territory. It not only made it to the end of the required period, it showed no sign that it was anywhere near a failure. That specific grease was an essential part of the design and a version of that test became a part of the production acceptance test procedure. When we built our RV-6A I was very careful to buy and apply the exact lubricants specified even tough they were some times hard to locate (even in the USA) and the minimum volume was larger than I would ever use in a lifetime. Those lubricants are itemized on my annual condition check list and nearing 1,000 hours of operation I have never had a lubrication failure.
Since your manufacturer is claiming the failure was due to the lubrication, I think it is likely the cause as well but compliance with the installation procedure is critical too. I wish you luck with the new one, I can only imagine how you felt when this happened to your airplane. However it performs when you get everything restored it would be a very good thing to come back to this thread and post your experience.
Bob Axsom