It’s not so weird that the displayed map and the nodes don’t always match.
The displayed map on this site is generated by a different site (https://www.mapbox.com/) which is also based on OpenStreetMap. It gets regularly updated, and is merely a visual representation of the underlying OSM data.
The nodes, on the other hand, are what this site imports directly from OSM to determine what the roads are and whether you’ve completed one. Updating this data turns out to be non-trivial, and is the current source of many headaches.
Several times I’ve changed a road in OSM and seen the visible change on the map within a week. Yet the old node existed long after the visual map changed, resulting in a node in the middle of a field. At least until the next time the city was updated. (My home city was last updated on October 10.)