Over the weekend, I was experimenting with how I could get subtasks to appear in the Active Sprints view, and now issues only appear in the Active Sprint – the backlog and future sprints are empty. Searching for changes that would do this, I found references to (1) unmapped statuses, and (2) swimlane configuration. However, following the instructions in those posts aren't helping.
All the status types are mapped to columns:
board column configuration.png
In my experiments, I did try changing how the Swimlanes were mapped. I don't see that affecting the visibility of issues when I change it around now. Currently, Swimlanes are based on Stories:
board swimlanes config.png
I did NOT do any experimentation with changing queries.