When adding a sequence of entries, parent, child, grand-child... and the grand-child entry is added on a different server than its ancestors, the conflict resolution is incorrect and the grand-child entry is hook to the top entry of the backend.
The issue is exercised when the Adds are replicated to a 3rd replica (which may be a little bit behind).
Here's the result when adding 5 entries one under each other, but the 4th one is done on server 2.
I've created a unit test for this issue: org.opends.server.replication.DependencyTest.addMultipleServersDependencyTest()
When committed, the test will be disabled by default.
To run it, enable the test and run: