That is odd, indeed. Your code looks clean, too, so it should drop to the bottom. I don’t know whether you’re using Incognito Mode in Chrome, but you definitely should, to avoid some odd behaviors. When you’re not in Incognito, some of your Chrome extensions might get in the way, use up memory and mess the results. If you tested using Incognito, that’s even stranger.
Remember that in the first case, nodes also should go down to the bottom, because the node was removed but still has a retained path. If you just look at the nodes you could have a false positive of sorts. In this case, I recommend using the Heap Snapshots comparison, to ensure that it is indeed a memory leak; it’s more detailed and reliable than Timeline for this.
Thanks for your contribution and for testing this!