Arnaud,
We checked all fuel related set-up and everything was fine. No bubbles in the system at all. We did not check the last two points of your contribution (i.e. rpm sensor). My contention is that this problem is software related because it can't be that if there were bubbles in the system the turbine would always stop at approximately the same rpm/temperature position.
I think you made the wisest decision of getting the software upgraded thereby eliminating the problem with a fresh reinstallation. Probably that is the route we have to eventually take in due course but I am playing for time to see whether any of our friends here had a similar experience and what was their solution.

Thanks all for your help. It is appreciated.

Reuben