Simple animation with 1 bone acting weird when scaled

This is a box rigged with 1 bone and simple animation. The smaller one animates correctly, doing 30 degrees rotation. The bigger one is scaled on Z by 2 (1,1,2 scale) and as you can see, it rotates only half a way in the animation. The animation is the same.
On the right you can see skeletal meshes without animation, rotated by 30 degrees and looking just like it should look.

Is this a bug? How can I make this bigger box rotate the same amount as smaller one?

PS. Same thing happens in Blender if you don’t ‘Apply scale’ after scaling. But there’s no way to ‘apply scale’ in UE after scaling an actor… This is… Strange?

Edit: I’ve just made an animation inside UE to make sure that’s not this specific animation what causes that. And results are the same: