Thanks for sharing the export settings.
It seems as if the export issue is a bug related to Spine version 3.8.79 (incorrectly stripping some whitespace at a mesh), after upgrading to Spine 3.8.81, the problem no longer occurs.
Regarding your setup: Please note that you should not use meshes in form of a quad for your wings, you could as well use a normal Region Attachment
, which would allow for automatic whitespace stripping. When you currently export your atlas textures, it contains lots of unnecessary whitespace due to using Mesh Attachments
. Unless you are planning on editing the meshes later to fit the image, then of course ignore the lines above.