Story time!
Now, I knew I'd addressed this problem in the past, but it wasn't specifically for Skaven. I fixed the issue, and checked it was working properly on a few armies. When it seemed to be working, I smiled and moved on. Skaven, being near the bottom of the list of armies, was never reached, but I assumed if it was working with others, there would be no reason it didn't work for them.
What it boiled down to was how AB was dealing with preselected armour. For everyone except the Skaven Warlord and Chieftain, it gave the no armour save unless the preselected armour was selected, so when a different piece of armour was selected this line of code was ignored. But not our two Skaven friends! For some reason, their code was the reverse - the preselected armour save was hard-coded into their stats, and it was modified if another piece of armour was selected.
This simple reversal of stats conflicted with how the Armour of Silvered Steel was implemented, causing an error with just these two characters.
Short version - it works now, just re-download the file
