Crap. I think it would have been a two second solution if it was still around.
(although I think any other instance would also work, such as access to a friend’s Dashboard)
The cookie is set at the time of the dropdown switch in your picture above.
I think the goal should be to add another instance below that, then make the switch (there and back, pausing between), and then check your settings. (using a browser that does not have strict cookie rules in place)
I know, a lot of hoops… but it really sounds like a cookie just needs to be set.