Achievement : Lost Scull (Horses can't swim)
You can call it a typo a bug or whatever... i just did the adv without noticing the exact description of this achievement and i only based my troop setups on the titles. Used mostly soldiers as losses and it ended up not completed. And then i noticed the description...
http://i.imgur.com/SgUofcp.png
The Lost Skull - achievement bug
The Lost Skull - 'Horses Can't Swim' has bug. Quest is 'Complete "The Lost Skull" without using any cavalry', but in list of units is cavalry but it's missing soldiers.
screenshot