Slitherine

I have seen this issue being reported previously. When, after moving a unit, game does not synchronize its icon and current position. But the reason I am bringing this up is because I have a test scenario capable of recreating the issue. Scenario where to test it is attached below.

The way this was achieved was by enabling already enabled trigger.

Steps to recreate the issue. Select US infantry and move it to hex marked with bronze flag. Hit end turn.
Select US infantry and move it to hex marked with silver flag. Flag will change ownership but unit and supply boundaries will not be updated. Hovering over highlighted, possible to move hexes, will result in an arrow pointing direction where to move coming from hex marked with silver flag although no unit is shown there. Hit end turn.
Supply boundaries will be updated but unit icon will not be updated. It is impossible to select unit where its icon is but it is possible to select invisible unit on hex marked with silver flag. Select and move it. Situation on the map will be updated.

Looks like your Unlock Commander trigger effect is linking to a unit which no longer exists (been deleted). I've added a safety check so that doesn't break the code.

Had another occurrence of ghost unit, this time in Philippines scenario. Save game is attached as well as options file just in case. On the right side of the map there is engineer unit siting on a bridge. Japanese tank is next to it. If you decide to blow bridge you can do it but after selecting adjacent hex where to go unit stays on bridge during and after explosion but it can be selected on the hex where it was ordered to move. Was able to reproduce situation twice to be sure.

BTW off topic observation. Building pontoon bridge with engineers while playing on 2D map does not provide any visual indicator of the bridge across the river.