after some research i found:
in RQ2 - page 86 - Attacks and Parries: "Attack and parry rolls are subject to the ‘Opposed Skills Over 100%’ rule on p35, despite not strictly being an Opposed Test."
in Legend Core this sentence is deleted.
Does this means that the "over 100%" rule cannot be applied to a combat contest?
For me, it shouldn't be applied, but.. maybe there is something i don't understand well.
Just to clarify the above quote from the MRQ2 book: Attack vs Parry rolls are not Opposed tests, as both can succeed without reference to each other, you don't need to roll higher on your Parry than the attacker rolled on their attack. They are still subject to the rule of adjusting skill levels down by the amount over 100% of the higher skill level once situational modifiers have been applied.
It is important therefore for the Attacker to wait for a Parry to be declared before rolling, as per the rules. It appears that, as others have said, Legend cut this thus leading to the confusion. RQ6 maintains the rule applying in its description of "Differential contests", it's term for the kinds of test used in combat. It also warns that the defender needs to declare before the attack roll even more so when their own skill is greater than 100% as if they don't it can lead to the confusion of attack rolls at first hitting, then missing.