I noticed this in an internal instance and I just reproduced it here on meta:
- Go to a category, such as #plugin:extras (where you did not customise your notification setting yet, so it defaults to Normal).
- Change the setting to anything else, e.g. Muted.
- Reload the page using your browser (e.g. F5).
- If the setting is as expected, try changing to another setting (including Normal).
If the setting is not as expected, that’s the bug.
Sometimes the settings are applied, but more often they are not, in particular when switching between Normal, Watching and Muted (but this last observation could just be my impression).
(Workaround: Go to the user preferences and set them there – don’t forget to Save Changes.)
P.S.: While the XHR HTTP POSTs to the notifications endpoint yield a
HTTP 200, I noticed that they submit the
notification_level as a string (i.e. “0” for Muted, “1” for Normal up to
"3" for Watching), but maybe this is intentional and not the problem.