Delays in ticket assignment and re-assignments of already assigned tickets were observed for some accounts from 2015-11-12 19:50:28 UTC to 2015-11-12 21:30:13 UTC duration 1 h 40 min.
At 21:30 UTC the issue had been solved, the system started working normal
What was it
This is the bug which manifests itself at load peaks. This happened for the reason that the system is not had time to fulfill the assignment of the ticket in Zendesk before start a new cycle.