Not sure if this is a bug or it is a result of our workflow, but....
When an issue without an assignee has its status changed from Open to Resolved and Resolution is changed to Fixed, the email notifications sent out show Last Change as the Assignee changed: Unassigned --> Unassigned.
We only have 2 developers in house (one does UI and one does backend DB) so our tickets are opened without an assignment. The 2 developers look at the open issue and figure out which ones are theirs and correct the bug. If they don't assign the issue to themselves and change the status to resolved, the email notifications are sent showing the Last Change as "Last Change: Assignee changed: Unassigned --> Unassigned" rather than the Status change for the "Last Change" field.
Thanks for any input.