If you mean the blue node that's connected to the yellow node beneath it, I think it's actually connected to the yellow node beneath that one (the one that is d

If you mean the blue node that's connected to the yellow node beneath it, I think it's actually connected to the yellow node beneath that one (the one that is distance 1 from the blue node :) ), and the edge happens to travel very close to the closer yellow node so that it looks like it intersects it. If those three nodes (blue, yellow, yellow) were in fact connected by short edges, then another problem would be that the two yellow nodes were connected, which they couldn't be by the constraints of the original problem.