Stealth unit partial info after fellow troops killed

I noticed that if I kill all units in a stack except the stealth unit(s) I can still see the location but not the identity of the unit(s), like the "far view" of units. I'm wondering under what conditions this occurs. Are there scenarios other than the above where this can happen? How about, for example, if you "mark" a stealth unit with a patrol tic while the stealth unit is scouted?

ps. I don't think I had any scout units (e.g. ACs) within far view range which is what made me wonder, but now I can't remember how well I actually checked this. It was in a prov owned by me, but I don't think that affects spotting stealth units does it?