Fix and solve the problem with animation

Offering remote work. You need to fix and solve the problem with the animation of the wings of a bird in Unity.package. There is unity.package which contains animation of 3D model of the bird, element of environment (branch) and sound. The model is configured and the package works correctly. When importing content into the AR application, a bug with wings occurs, some of the feathers disappear. In the attachment 2 screenshot, 1st - removed from the package in Unity and there is no bug, but there is an understanding of what should look like wings on AR. 2nd screen from the AR app and it shows the problem (part of the wings are missing). The app is assembled on Unity 2018.3.3f1 and is used by Vuforia 8.0.10