WordPress 5.2.2 dubbed a short-cycle maintenance release is available for download. This release addresses 13 bugs and improves the Site Heath features introduced in 5.2.
One of the changes in 5.2.2 affects the theme update link in the Customizer of multisite installs. The update link for themes on multisite installs in the Customizer has been removed. This is because updates can not be performed from within the Customizer in this situation.