First of all this problem is not created by the latest FW update. I have this bug now for a while in the android naim app. Not a big deal, cause it plays the tracks listed in your playlist. But I was wondering if more people have this problem. When I create a playlist it makes two of them. When you delete one of them the other one is still there but it is an empty playlist without tracks. When you click and scroll around in the naim app then the empty playlist is suddenly gone. I tried to make a playlist in the desktop version of tidal. Nothing wrong, creates one playlist. I go to the Naim app and I see again two of them.
I had a similar problem on a non Naim device. Try renaming one of the duplicates in the Naim app then delete the empty one from the Tidal app.