Harald I'm afraid we need more information in order to be able to help. Which version of the spine-unity runtime are you using (name of the unitypackage, also listed in Assets/Spine/version.txt)? Which skeleton component are you using (SkeletonAnimation, SkeletonMecanim or SkeletonGraphic)? Are you using special blend modes at the problematic attachment's slots? What are your atlas export settings in Spine? What are your texture import settings of the atlas textures in Unity? Please be sure to check whether the export and import settings match, as described here: http://esotericsoftware.com/spine-unity#Advanced---Premultiplied-vs-Straight-Alpha-Import
