If I understood your question correctly, then you have the problem that you can successfully replace a region attachment, but replacement fails (with strange vertex placement) when replacing a mesh attachment.
This is due to the very limited nature of the old legacy example component SpriteAttacher
, which is limited to attachments of type RegionAttachment, it will replace an existing MeshAttachment with an un-deformed RegionAttachment which will animate and place vertices incorrectly.
Please instead check out the example scenes Spine Examples/Other Examples/Mix and Match Skins
, Mix and Match
and Mix and Match Equip
.
You may also want to check out the spine-unity documentation section Combining Skins
below:
spine-unity Runtime Documentation: Combining Skins