Enhanced (coloured) hair-like line at the your tile edge.
What to do:
-Firstly select your pattern then Object > Expand click OK on the dialog (Fill should be checked by default if not check it)
-Select your pattern (make sure your design is selected) then Right mouse click and ungroup
-Now Right click and select release clipping mask (this will reveal the pattern Illustrator creates)
-Open Pathfinder (Window > Pathfinder), Select your pattern and click Merge in Pathfinder window. (This could take a few minutes)
Your design should look perfect and cleared from any lines!