Hmm, that's interesting. That is a bit like how their mobile app works.

I wonder if you are part of an "experiment"? Google routinely conducts experiments on its users. To escape an experiment, you can try clearing your cache and your Yahoo cookies. Sometimes the experiment returns when you log in again...

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click (on Mac Ctrl+click) a blank area of the page and choose View Page Info > Security > "Clear Cookies and Site Data"
• (menu bar) Tools > Page Info > Security > "Clear Cookies and Site Data"
• click the padlock or "i" icon in the address bar, then the ">" button, then More Information, and finally the "Clear Cookies and Site Data" button

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Then try reloading the page. Does that help?

Cookies and cache are always clean. I do it multiple times a day using CCleaner. As for your other suggestions I tried them with no effect.

Okay, I went to Google's forums for a look-see.

You don't have the setting here?

https://www.youtube.com/account_playback

According to a user in another thread, the on/off is stored in a cookie, so if you clear that particular cookie, you have to turn it off again:

Mini Player keeps re-enabling - Google Product Forums

Anyway, I think Google is in a better position to respond to further questions than we are.