Chrome Version: 73.0.3664.0 (Canary).
OS: Windows

If you left-click on the up arrow for an item in the download shelf, it points down while there's a popup menu.  Dismiss the menu, and it points up again.

However, if you left-click on the down arrow a second time while the popup menu is displayed, and then dismiss the popup (It doesn't seem to matter how - left click elsewhere on the download shelf, left click another window, right click on something, etc), then the arrow still points down.

Mousing over the arrow a few times while it's pointing down generally fixes the issue.  I can't reproduce on stable, though I am using a dark theme on Canary and not stable, so it may be related to using a dark theme.

Anyhow, just a minor polish issue.  Not sure it's worth investigating, but thought I'd file a bug for it, anyways.