I'm not saying you are right or wrong about the Motul stuff being the cause, but hard to make that call based on one person's failure. If there were more failures on Motul, then yes, for sure....
With that being said, I would never use something (Motul 300) that was so drastically different from oem spec. I don't claim to be an expert on these things and would not want to chance it.
I would try the ravenol mtf-2, since it's within spec.
FYI, I am on the oem fluid, but at 2 liters. I had to buy 3 quarts to get there [emoji36] .....1.89 liters is close but I wanted (needed, if I wanted to be able to sleep at night) to be precise.