Problem with verticality (Y pos != 0)

Hey guys,

I'm working on a project that have verticle gameplay (plataforms not so different than in Mario Bros), and when the plataforms where included, we noticed that whenever a character Y position is not zero, every hit is treated as if it have KnockDown proprieties (maybe the character is beign treated as if he's jumping/falling/airborne?). He IS grounded and his verticalForce is zero.

Does anyone have any idea where the code checks if the oponent is on ground or air when hit?

Thanks in advance!