AnimationUtils.subclip results in weird animation

I purchased a model on sketchfab. All the animations are contained within a single animation clip, which I am turning into separate clips using AnimationUtils.subclip. (The exact start and end frame of the animation doesn’t mentioned, so I had to guess)
In this example I tried to separate the walking animation, but the wings are going into a weird pose, which is not present in the original animation clip. Do you have any ideas why is it happening?

Is it possible some part of the values for wings are set in the trimmed-out part of the clip? Thus when you take only the walking fragment, the wings will not be properly positioned. This might happen when the animation is additive.

Thanks @PavelBoytchev . Is there any way to work around that programatically? Or does the animation has to be modified on the model?