I noticed a few things playing this campaign in 1.8.4, and didn't see anything in the changelogs indicating that these scenarios had been updated.
I was surprised, when I lost High Pass the first time around, that I simply got the standard "You are defeated!" message. I'd been re-reading ESR's campaign design how-to, and remembered that he specifically mentioned a character lament that they were snowed in till spring, as an example of 1337 writing. I looked, and the line that was supposed to trigger it read "event=time over" instead of "name." (As others have mentioned in feedback, objectives aren't updated to note that Ratheln's death was a victory condition.)
I also looked at Invaders, and saw something strange about the enemy gold. One orc leader goes from 220 to 260 to 300 gold. But the other two go from 180 to 220 to 360 gold. Obviously, players have been able to beat this scenario as is (as did I, with painful losses), but is it possible that it wasn't actually intended to be quite as tough? Is there some reason ESR wanted the other two leaders to go from having less gold than the other, to more on hard?
Also, in Court of Karrag, the objectives don't mention that Dulcatulos is a can't-lose character, although his crown alerts players to this.