Unity UI [Solved] Is the RectTransform automatically changing at runtime intended behavior?

I have a canvas GameObject with an Image GameObject as child. On the prefab, the image rect transform is set to stretch the whole screen (top/bottom/right/left = 0) but at runtime, the rect transform is set to bottom left corner and doesn't take the whole screen (maybe about 66%).

 

Figured it out. The child object had a canvas scaler and it was getting resized because of it.