Pretty positive this was working fine earlier this week. When I click on a project task in Kanban view, then use the stage named arrows in the top right to move it to a different stage (specifically one I can't see in Kanban view because it's currently unoccupied), the arrow doesn't turn blue, and the project stage is just dumped into "Undefined."

I double checked the numbering sequence of my project stages, and they're all intact. Not sure what else it could be. Suggestions?

Edit: This is also happening with Kanban view for opportunities I just noticed.