Steps:
1. create many languages for an object
2. create a copy of it via the copy option in context menu
3. run content sync

Expected result: all current languages are synced

Actual result: not

Analysis:

• content/copy action creates an object at version X (X can be > 1), having many languages and possibly even a sort-order not corresponding to the default sort order of the content class
• the sync events are designed to only create one language each, and only 1 event is created at the time of object copy

Suggested solution:
improve the custom staging worfklow event tied to post-publish so that it detects when a publication is happening because of a copy, and creates many sync events (one per language plus possibly one for the sort order)

Alternative solution:
make it possible for sync events to handle many languages in a single object-upsert http call.

The second solution is imho too complicated, while I have a POC for the first solution, which will be sent as Pull request