Ok, thanks for the information, it sounds like a problem in the Intermediate Levers but can be other problems also.
Regarding the warranty, it is a fault and should be fixed whatever the cause is even if a new engine needs to be fitted, it is up to the certified workshop to deal with issue until it is fixed and the warranty should cover all the costs. I would say like this, if the workshop says that first we need to check the intermediate levers before doing more things then it should be included in the repair plan of the car even if the levers were good.
Cheers