FBX animation great in Legacy mode, leg animation screwed in Humanoid mode?

Any ideas why would animation work OK in legacy mode, but wil be screwed up in Humanoid mode? All bones bound to avatar correctly, animation is baked in every frame, but legs move differently in legacy and humanoid modes. 0_o

Do you have any warning in the importer?
select your imported file and click on the animation tab, check out for any warning or error in the message foldout

Does your avatar t-pose is setup correctly?
take a look at this blog post, more precisely on the T-pose section

Yes, Avatar configured properly, all test animation sliders causes expected movement of model. And why left and right feet behave diferently if animation should move them exactly the same way. And in legacy mode they move as expected. I can send you my model and animation FBX files if you want.

yes please log a bug and we will take a look