Huh, I got something weird to happen just now with the C&C Napoleonics Vimiero scenario which sounds like the reverse of what was reported: If I open the scenario, close it, reopen it, choose a command deck, and then undo that, the deck doesn’t disappear, but the button comes back! That’s goofy.
I suspect that this is the same problem you guys are seeing but manifesting itself a bit differently for me. I can reproduce this, at least, so I’m going to see about fixing it next.