Are you using duplicates of the exact same eye? If so, only one of them may be exported when Alias(去除重複) is enabled in the texture packer settings. When Alias is enabled, two images that are pixel for pixel the same will only be packed once. However, the skeleton should be displayed correctly at runtime. If you want to pack all of the images even if they have the same pixels as others, uncheck Alias.

Also, please make sure the Export(导出) option is checked on the mesh attachment's properties:
附件 - Spine用户指南: 导出
If unchecked, it will be excluded during texture packing.

If the above does not solve the problem, could you please send your Spine project with just the eyes part to us via email? : contact@esotericsoftware.com

Thank you for sending your Spine project. I confirmed the issue can be reproduced. It seems to be a bug that occurs when Polygons(多边形) packing and Strip whitespace X/Y are used at the same time, but unfortunately 3.8 is no longer being updated, so please use Rectangles(矩形) packing instead of Polygons and disable Strip whitespace X/Y, or separate images of both eyes into one eye each.

Yes, we will not update Spine 3.8 in the future I'm afraid. Fortunately, this issue can be avoided, so please try the workarounds as described in my previous reply.