Not allowed to move into hex with invisible unit?

[Liebchen]

This is not a case of a hidden unit.  The unit image is just missing.  Seen this before in testing new titles and updates.

Paul, you are correct that Liebchen should be able to attack the unit.  This would be tricky since he has not idea what he is up against.  Fire or assault one the hex would only tell him the unit type or types such as enemy casualties of men, vehicles or guns.  This would not be much good though in HTH play to identify strength, whether the vehicles (if encountered are hard or soft and number of counters in the hex and their approximate sizes.

I asked for more information about the game title and scenario.  Not much to go on so far except the problem is on Liebchen's game and not on his opponent's game.  A bit of an assumption on my part, but not too much of a stretch I think. 
WDS could possibly sort this out with a saved game file.

As Paul reiterated, I cannot even assault the "Claude Rains" unit. Ergo, there is actually no unit there.