When I created a new workflow, in parallel in Production and the Sandbox, I added a new first status, connected Create to it, and removed the old first status, "To Do". I didn't observe that that action changed the name of the first status in 43 workflows (not all may be active). An admin has tried to remedy this at least in boards, but I don't know how to fix it short of copying each workflow, modifying the copy, adding it, deleting the old, and moving all issues to the new workflow--43 times. The new workflow was published. It was only added to one test project in Production (and the same project in the Sandbox), so I assumed it would not affect any other workflows. I don't remember seeing a warning during the switch in first statuses, that my actions would affect other workflows.
I actually created a second workflow after that, and noticed that the first status was now the new name instead of To Do, which should have told me that something was wrong, and I repeated the same procedure: Added a new status, connected Create to it, and removed the old status.
Is there anything our admin can do to fix workflows and boards?
In a chat, Atlassian Support suggested changing the name back in any workflow, and that appears to have worked. An admin made some changes yesterday in individual projects, and had to move issues back into "To Do" today.
I was sure I had added a new status, connected the Create transition to it, and removed "To Do", which I would think would have left every issue in To Do without a status.
The lesson would seem to be to leave "To Do" or "Open" in place, and add new statuses after that one.