We are experiencing the following problem with our spines: Attachments that should have transparency are getting black or white borders when they are placed in the scene. Since we are often using different eye and/or mouth shapes we are experiencing this problem quite frequently.
If you look closely you can see a line around the eye area.
Currently our workaround is to switch out the whole head or even the whole character is some cases.
This alpha issue seems to be affecting mainly iOS devices, where the lines appear to be more prominent. If basis compression is applied to the texture, the outline disappears, however it leads to a lesser quality of the spine itself, which is not necessaritly what we want either.
We have tried all differend kinds of export/import settings in spine and playcanvas but so far nothing has helped. We prepared a small sample scene where the problem can be seen.
A build of this project can be found here. (or scan the QR code below)