The mystery of the missing walls

[Ziu]

I took Pataviun from the Brutii and built the walls up to epic size.
As this is a frontier settlement for me (Seleucid) it is constantly being sieged by the Romans.
The only problem is, when I sally to beat them of I have no epic walls!!
Not even large stone! Only piddling stone walls. Where are they!
They appear on the settlement scroll but not on the battle map!!!

[discovery1]

I think there's a bug where the grand walls appear as the level below that for all but the romans. There may have been a fix, but I forget.