The right team has been informed of this and they are currently looking into it. Head over to this Ongoing Issue thread and add your +Vote and the requested info as a post. Don't forget to Subscribe to the thread in order to stay up to date with any development on the matter.
In the mean time you can try managing the playlists and folders on your account from the Desktop app if you have access to one. In there you can simply drag items in and out of folders.
Hope this helps.
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