This issue seems related to a known problem where the first selected bone does not bind correctly when multiple bones are selected for binding to an image. This was identified in previous versions and improvements have been made in later versions of Spine. Since version 3.8 is no longer being updated, it is recommended to upgrade to a newer version where such issues have been addressed. In newer versions, enhancements have been made to the binding process, allowing for more efficient and accurate binding of bones to images.
