media library assets not showing in page builder but when I add new assets they show show normally.
need to revert to legacy mode to use old assets
Thanks for reporting this. The Page Builder team has been diligently working on rebuilding the entire editing experience, which will include enhancing the current media library experience. There will be small issues like this that will pop up and get fixed as they make progress.
I'll let the team know about this so that they are able to include a fix for it as soon as they are able. For now, you can continue to use the legacy mode as you've already discovered. If you'd like to permanently revert back to legacy mode to save you from switching each time, just let me know.