There are some issues with this tilesheet and many of the other tilesheets for this game. It appears that you may have simply flipped some of the textures instead of posting the appropriate textures for many of the water and ground transition tiles. The tiles in the corners of a transition between a grassy area to a pond (middle left on this image) are supposed to have different corners on the top corners than the bottom corners. The side tiles are also not supposed to be flipped when going down; there is a pixel on the side that looks like it is pointing up at an angle and it is always supposed to be pointing up no matter the side of the pond it is on. Please compare what you have here to what is displayed in the overworld map. This sheet is not the only one that has this problem; there are also some issues in the cliff and water textures.