@Aggressor Please note that when using spine-unity, you should not call Update or Apply manually and let the SkeletonAnimation component do it automatically.

You could check your above code in complete isolation in a new Unity project with just your problematic asset present. If this still occurs, you can send us this minimal Unity project as a zip package to contact@esotericsoftware.com.

@Aggressor:
Are your checks done at runtime/play mode or in the editor? 'cause there's some weird stuff about sprite textures not having their packed versions returned unless it's actually at runtime.