AppleWatch 3 Series shows 4 lines of stripes across the display My AppleWatch 3 Series (GPS model) is showing 4 lines of stripes across the screen when it is off and under a direct light.

Should I go to AppleStore to check it? Or that is normal?
According to this article on MacRumors, there's been some defective Series 3 displays.  Apple is replacing them under warranty.

If it looks similar to this image, you should have no problem getting Apple to fix it.