Uberto,
One more feedback:
Yesterday, I flew again my flight LFML>LSGG with the intention to check frequently if Couatl engine was still running during the whole flight, not only on arrival approach and I was surprised to see it had already crashed, when I tested for the first time, just after reaching my cruise level 280. So I restarted it manually and it didn't crashed again during the whole rest of the flight.
Hope this info might help.