== Reproducible: == Always
== Steps to Reproduce: ==
User1 opens and edits the Ticket1 with blank at Relationships field.
User2 adds a relationship from Ticket2 to Ticket1, and then saves it.
User1 saves the Ticket1.
== Actual results: == Ticket1 is succeeded to save with no relationships when User1 submitted. Because the relationships is overwritten after User2 submitted the changes.
== Expected Results: == It failed to save Ticket1 when User1 submitted and occurred the conflict warnings.