Go to iTunes in the computer you don't want the iTunes playlist showing up in, & go to iTunes preferences (under the iTunes name next to apple icon top left of screen), choose Sharing tab, disable Look for Shared Music option. I think that will fix it. If not, disable the other share options. If still no good, do the same in the other iTunes on the original computer. My partner hates my LW playlist showing up on her iTunes on her computer.