Always reposition the annotation view using the standard -setCenter: setter, fixing KVO compliance for the center key path and making the view behave more like a normal view. -setCenter: updates the transform by side effect, and it always starts from the identity transform to avoid surprises. To apply a custom transform on an annotation view, make sure to apply it in -mapView:didFinishLoadingFrame:fullyRendered: based on the existing transform.
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