Phab-02 is sending old copies of the stylesheet and is causing graphical glitches in the interface such as small icons, breadcrumb nav broken, and persistent column to be enabled.
Seems to happen when editing various settings in Differential. The currently served stylesheet (https://phab-02.wmflabs.org/res/phabricator/f1eab25d/core.pkg.css) is different from a different hashed stylesheet (https://phab-02.wmflabs.org/res/phabricator/aaaaaaaa/core.pkg.css). This may be caused by sendfile in nginx in the project proxy (http://stackoverflow.com/questions/6236078/how-to-clear-the-cache-of-nginx). Sendfile is used to send static copies of files and may be doing this with the stylesheets.