It's documented behavior rather than a bug, but it's easy to miss because the doc lives on a different class than the one people call.

The nasty part is what happens when the cap hits. Per the docs, the search / resets and builds a path from the start polygon to the polygon that was found closest to the target position so far. So you don't get an empty path or an error you get a plausible-looking path that ends short. That reads exactly like a disconnected island.