Fast Ring Insiders for Windows 10 should see build 15048 available for download. A few fixes this build. A couple more known bugs, as well. As always – please read the release notes from the blog page. I see a lot of posts in various forums mentioning, complaining, and reporting these known and documented bugs.
Insiders with multiple monitors may encounter an issue where one of the monitors stops rendering (with the exception of the mouse). While rebooting will fix it, you can also resolve the issue via Settings > System > Display under the Multiple displays section, set it to only use the monitor that’s functional, then set it back to “Extend these displays” and the issue should be resolved.