Maybe not a bug, but I consider it to be one.
After running maintenance, if the last reply to a ticket is by a Helpdesk Admin, the ticket status is set to waiting staff response. I think that Helpdesk Admin should be considered staff in this case.
Is the helpdesk admin also a forum admin... if yes, is the option to treat admin separately from staff checked?
Yes, it's checked. Hadn't thought of that. But it actually turns out that it does consider helpdesk admins to be staff in the maintenance, but the maintenance needs to be run twice for it to get it right in all cases. The first time maintenance runs it figures out and corrects the setting of who is the last person to respond to a ticket. Then when you run maintenance again it corrects the status for those tickets where staff was the last to respond. You just need to run maintenance twice in a row for it to get it right.
I'm running this immediately after my Exdesk import, where there's 1700+ new tickets, which then require two SQL queries to run to get them correct. I'll post a full update in a publicly visible forum about how to update from Exdesk. There's a few twists.
After reviewing the code, it is supposed to function like this. What the code determines is if you have staff rights when it is correcting the status. If you are not a staff member, its triggers this as awaiting staff reply. To fix this, you simply need to make them staff members.
I will close this up in a few days as solved, since this is by design.