I've seen a similar bug in the shore campaign. I was tasked with taking out some tanks but once I reached the fence, 2 units of tanks radioed that they where ready to move and an option was added to F10 that allowed me to order them to move out. The only problem was no units had these names, the point they where supposed to be moving to didn't exist and there was nothing in the unit briefing about it. Just for fun I told them to move out but selecting either option didn't have an effect and once I destroyed the target specified in briefing, it gave me a mission complete dialog.
This happened again on another shore campaign mission when I was told to escort some tanks to a specified position. I flew in destroyed the targets and told my tanks to move in just to discover that they didn't exist. I was forced to quit the mission and take an incomplete mission and in the debrief screen there was no indication that any of my ground forces where destroyed and so I don't think they where ever spawned when the mission started.
It sound like you have the same thing. If you quit and take the mission failed, a new mission should be generated for you.