I don't know if this is a bug or i miss something

The Merchant
* +30% Income
* -25% Money Losses on Plunder Attacks
* Immunity to all Income Penalties (Riots, Plagues, etc.)
* Banks are twice as effective

I'm using undead/merchant now and i'm puzzled on something.
The other day, i had riot and greed done on me.
I notice that i have lowered income immediately and increased wage, isn't merchant supposed to be immune to those ops?