Hello people,
So basically I was exploring Godot as my first time around and I created a TileMap with a tilemap image set.

I imported the tileset with 2D Pixel preset and used the "New atlas" method. I have no clue why the resource is mirrored both horizontally and vertically. I don't know why this is happening.
I'm using the tileset from here and running Godot Engine v3.2.1.stable.official on Linux Mint 19.1 Cinnamon.