We have experienced the same problem with some coordinates in Germany. When we give lat and long the marker itself is placed correctly. If we want to calculate the route, the marker gets way off in lat and long.
We've tried with using the link setup like @BillwoodMarbles suggested and that kinda works. But when using this setup the dirflg parameter (which we use to tell Apple Maps that it should calculate the route for pedestrians, not cars for example) is ignored by Apple Maps.
macmyday
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