I create a sphere with earth texture. Rotate it around X axis. Then start animation (rotation around Y axis) but it doesn’t animate until I comment out initial rotation around X axis. Why?
It looks like the problem you’re having is that the rotate function sets the mesh’s rotationQuaternion property, which causes its rotation property to be ignored.
E.G. you could do your initial x rotation using the rotation property like the animation currently does, like below, or you could change your animation to use the rotationQuaternion property like the rotate function does.