Hey, since I updated PS, It looks like it "smooth" the pixel but doing that it creates one pixel clearer on the edge so basically when I want to repeat my tile I have a line of one pixel clearer which is not good.
Can you tell us what version of Photosho you are using? Can you also walk us through the process you use to create your pattern? Do you still have your original pattern file? I would suggest going back in and painting that one edge and then redefining it to see if it gets rid of the line.
f I can understand your problem then the problem is anti-aliased line, semi transparent line on side. Why this is happening? Because your shape is not aligned properly to pixel grid. Eiminate that line before creating pattern by repositioning shape to align to pixel grid or select entire shape including anti-aliased line and fill it with solid color then create pattern.