The initial 3.10.0 release tarball was missing some components resulting in upgrades using the previous version of the staff client and new installations not allowing staff access at all. A repaired 3.10.0a tarball is available on the downloads page. Installations directly from git were not affected.
If you have previously installed Evergreen 3.10.0 check the version reported in the staff client by opening the menu in the upper right and choosing About. If you do not see Evergreen Version 3.10.0 you should re-run the installation steps with the updated download.