After renaming an existing playlist, it shows the correct new name in the playlist selection. However, upon reloading the site, most of the time, the old name reappears, as if the renaming has never occurred. This behavior is also inconsistent. Example: I renamed all of my 20 playlists to include an emoji in one sitting. And even though the site displayed them all without issue after I was finished, once I closed the page and returned to it later, only 3 (seemingly randomly chosen) names retained the change. All other playlists reverted to their original emoji-less name.
Now, trying to change just a single name only works (if at all) after many tries of renaming, reloading, seeing that the change was not permanent and trying again.