The new fishing game out on the Kumos server is currently using a 20x20 map for Intermediate level, but says in the instructions it should be 15x15. One of those must be an error. XD
(Edit: Also chose "Peaceful Pond" for that game) (Edit 2: It's been a few days but I've just noticed that the difficulty selection box already says 20x20. The guide on the starting page still claim it will be 15x15 however.) it's been over a month and this (presumed typo) is still on the fishing guide https://kumos.subeta.net/games/fishing