I have a setup with two languages and two nodes (one 'en' and one 'de'). The content type has a image field that allows multiple uploads. The field is set up to synchronize.
When I upload the first image to the 'en'-node and save the node it says: „One node translation has been synchronized.“ But the image doesn't appear in the 'de'-node. A look at the database reveals that there is indeed an entry for the 'de'-node in field_data_field_* but it's language is set to 'und'.
- After manually setting the language to 'de' the image can be seen in the 'de'-node as expected.
- Uploading more images works just fine.
- Deleting all images in the field, saving the node, uploading a new one and the bug is visible again.