Go to the schematic, right click on the component and select "Attach Pattern". If you hover your mouse over the pads, you'll see that they're connected to each other. When you changed the pattern, you accidentally also dragged a ratline from pad1 to pad2. If you want to see this better, in the Attach Pattern view, move the component a bit so that you can clearly see the ratlines (just right click in the window and drag, just like scrolling in the PCB or Schematic view). The ratline in question is an error, and shows up red, I think. To fix, simply click and drag a ratline from pad1 to pad2 again, and it will ask if you want to disconnect the one that's there. Do that, and your problem is solved.