Weird layout of Spotify Web Player on Firefox on Windows 10

[naturallyherb]

I run the Spotify Web Player through open.spotify.com and I noticed that the longer I use Firefox, the Spotify Player changes to a weird layout that I cannot revert back to the standard Web Player layout, unless I restart the browser which returns to normal. In the weird layout it is almost impossible to access my library and playlists. Compare these two situations in the attached screenshots. Any idea how to fix this?

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First picture: Spotify normal layout accessed immediately after I open Firefox

Spotify normal layout on FirefoxWeird Spotify layout on Firefox that I cannot revert back unless I close the browserSecond picture: weird Spotify layout appears after I used Firefox for a while (after lots of opened tabs) which I cannot revert back to normal layout unless I quit the browser. Lots of enlarged pictures, awkward interface, impossible to access playlists/library/etc.