pfSense

If you have more then 9 alerts, the formatting of the menu bar can break on most browsers.

Firefox 45 on Linux Mint 17.3: OK (Top of the image)
Chromium 48.0.2564.116 on Linux Mint 17.3: Broken (Bottom of the image)
Safari 9.0.3 on OS X 10.11.3: Broken
Firefox 45 on OS X 10.11.3: Broken
Chrome 49.0.2623.87 OS X 10.11.3: Broken
Firefox 45 on Windows 10: Broken
Chrome 48 and 49 on Windows 10: Broken

To replicate, just run this a dozen or so times in PHP Execute under Diag > Command:

file_notice("aaa", "bbb");