Serbia '14

[Volcano Man]

Did the Serbian Army destroy bridges as it retreated during the Fourth Invasion? Bridges in scenarios with a later start date are largely intact.

Not that I am aware of. It could be that they did, but I didn't want to guess. I only try to destroy bridges that I 100% know were destroyed in reality. But if you are referring to a specific later start scenario then I can take a look. There is always a concern though that if bridge destruction is assumed, then units may not be able to make historical movements.

Is it working as intended when naval units block ferry hexes? It seems the game somehow sees the naval unit as a unit using the ferry hex, so a ground unit can't move into the hex. When a ground unit is in the hex using the ferry, naval units can move in and out of the hex freely.

Right, as Darran covered (thanks), that is correct behavior. Its a technical limitation, mainly because we don't want to get into a whole mixed naval and ground unit stacking limit. So its best to treat the monitor (or monitors) in a hex like another ferried "group" of ground units, that is, once a group of ferried ground units are in a hex, you cannot have another unit, or group of units, move into the hex and also be ferried.

What kind of clever editor trick did you use for the invisible rail bridge across the Crna Reka north of Palikura?

Yep that is a bit of chrome there. 

Edit: in the Fourth Invasion campaign scenario, hexes 151,85 and 152,85 are shown as Field hexes on the map and have Field fire modifiers (-10%), but they contain RUBBLE.

Good find. As often happens, the map will be made and a scenario created, then some time later the map will be corrected. In this case it seems that the villages were thinned out to be more accurate, but it was after they were set to rubble in the scenario. I fixed this for the first update.