If you take the selectionAdornment sample, remove the fromSpot/toSpot and use Bezier curves for the links, the initial two curvature pivot points on the Bezier curve are sometimes set to the opposite side of the dragged component, so the arrow crosses the shape and comes in backwards.
Defining ‘sometimes’…
If the height of the node is (I think) less than double of the adornment button size, then if you drag from the top of the button the link is revered at the ‘To’ end, but if you drag from the bottom it’s correct.
I know it’s a weird set of circumstances, but this situation always arises if you try and apply the adornment drag-new-node feature to the State Machine sample, so it’s not quite as obscure as it first appears :)
Workaround for now is to the set the node template minSize height to at least 80.