Why does my texture look weird in editor?

Something is wrong with your png image. It’s the same for me, but after I re-saved the image it started to import normally.

Try to use a different image editor to save the image, or re-save it with some different options for png. I’m not sure what exact option is wrong here.

Or just use a different format, png is known to work not good with Unreal. For instance, try Targa (tga) format.