And by that I mean ways without nodes, i.e. things not imported to CS.
I’ve come across this before, cul-de-sacs that one does not really run to the end and turn around… Because at the end you can get to a road via a path (aka foot path, along with many other types of paths). In most cases the cul-de-sac, in OSM, is not connected to a path, but sometimes it is.
Route Builder is driven by Navigation & Routing APIs | Stadia Maps with its costing set to pedestrian. There are many trails/paths around me that look similar to what you have in your screenshot & Route Builder will send me through them …
Perhaps it’s a shorter distance from point to point to use Santa Fe Drive in the particular ways you’re clicking out the route? Like if your last click is on the upper Holland Lake Drive, in its roundabout, and then your next click is in the roundabout on the other Holland Lake Drive… It will have to route you through the path that exits down on Santa Fe Drive & the route tooling might ‘cost’ that as worse than just turning around and going down Clear Lake Road → Santa Fe Drive → Holland Lake Drive.
I’ve noticed this problem a lot in the USA (or at least, way more than I would ever in Belgium). People just don’t seem to connect paths to roads very often when mapping. I’ve seen many sidewalks just unconnected to anything, it’s rather annoying when plotting routes. Approaches to make the routing more useful:
Connect at intersections when there is the obvious intention that you can cross the road in some form (either marked crosswalk or just the sidewalk going up to the edge of the road).
Plot driveways that cross the footpath and attach to the main road. Now you don’t need to map all driveways, but if you plot some in strategic locations (near intersections or from time to time when the footpath has not been connected to the road very often), then the router can make use of those.
Sometimes an informal path can help, though I try not to add too many of those (unless when it is obvious a lot of people use it). You’re supposed to map what’s on the ground, so if it does not show at all it feels a bit wrong at times.