Since Moodle 3.5.3 the user menu in the top right and the gear icons have the cursor "auto" instead of "pointer". I observed this on https://demo.moodle.net/ with Chrome, Firefox and IE11. See attached screen recording.
The reason this appeared in Moodle 3.5.3 is because
MDL-62139 removed the href="#" from the <a> tag in theme/boost/templates/core/action_menu_trigger.mustache and lib/templates/action_menu_trigger.mustache: https://github.com/moodle/moodle/commit/e0f64e0feb2febf5173f766cb2e7f0ce4cd8372c This makes the user agent styles for clickable links no longer apply and you get the wrong cursor.
According to damyon in
Note that the <a> tags here don't have the .btn class.