Hello,
While setting up auto-tiling with the onsen tileset, if Im not mistaken, the seems to be two 3 cornered tiles that have the outside pattern in the top left, top right, and bottom left corners.
Meanwhile there's none for the type of tile that would have the outer pattern in the top left, top rot, and bottom right corners.

I'm not sure if Im missing something here, but I redownloaded this just to make sure.

Thanks,
Seven

Heya!

Thank you for pointing this out. I'm working on resolving it at the moment and will let you know when it's fixed and a new version is uploaded!