RESOLVED: Armies disappear

I just played a game were on several occasions my armies disappear. I attached with overwhelming force (3 or 4 times the defense of the enemy) and then my army disappear. The attacked city had the same number of units as before (all militia). It is possible for units, like marines, to remain hidden even in citys?

Yes, if you attack a city containing marines, etc. they will not show up even after a battle. They do however show up in the 'Battle' thing (can't remember its real name).

Marines and Subs become invisiable the moment they enter one of their own cities, and can only be discovered through combat.