Thank you Crab and Anthony,
May be my past participation to a few 350 accident investigations made me more cautious than I should in this forum. I am not in anyway saying that it cannot be a servo issue, but I have learned the hard way that not keeping a clean brain just hamper your ability to find the real root causes and may lead to improper hasty/easy conclusions.
I'll wait and see how it develops.
Fly safe
Kami