Chrome Version: 851431
OS: Linux, Windows, Mac

https://bugs.chromium.org/p/chromium/issues/detail?id=851431

We fixed this by clearing the array on route change. This is not desired. In download manager, we're able to fire('iron-resize') to rerender the iron-list, which while not ideal, it would be good to have a repeatable solution to this rendering problem.

Once the iron-list enters into this state of items not being rendered as they should, any scrolling will fix the issue immediately.