@spacecake
pls write exact coordinates (names) of the origin and the destination points.
i tried to simulate from Apeldoorn, Abrikozenweg 7 to London Piccadilly Circus 1 - looks fine, no quirks.
3790T, Full Map.
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as for the nüvi - check once more "Avoidances" section (somewhere in Tools/Navigation/Car/nüRoute) - i've had very funny experience