Sorry for the inconvenience here – during the release candidate for 25.0 we got a little ahead of our skis. What you’re seeing is Galaxy trying to use the visualization-first framework for previewing datasets (Visualization-First Display functionality by dannon · Pull Request #20190 · galaxyproject/galaxy · GitHub). Deployed on main, bam is currently configured to use igv.js, which isn’t quite yet available.
Thanks for the report, and we’ll get this resolved as soon as possible.