Comment 19 for bug 1803485

I haven't had a chance to do any routing since I identified the bug, so I can't be sure. Like I said though, I suspect it was due to the same bug causing lp:1804691, which is fixed. If anyone can make a reasonable determination through code analysis that fixing that bug might also fix this one by preventing the possible creation of zero-length tracks, then I think we can close this one until proven otherwise if it pops up again.