Sprints are duplicated when multiple issues are moved to a new sprint

Steps to reproduce

• Create a cloud to cloud synchronization with an issue type and Summary

• Enable to synchronize sprints by allowing Backbone to add new sprints

• Create some issues (~100 or more), create a sprint and then move the issues to the sprint (or create them directly in the sprint)

• Then check that the issues are synchronized into the partner project

Expected result

Backbone creates one new sprint in the partner project and adds all issues to it.

Actual result

Backbone creates multiple new sprints with the same name in the partner project and adds issues to different sprints.