The rules state that all revenue is lost from a province which is overrun by barbarian raids.
Does this even apply to negative results on State income? For example, the State Income of undeveloped Illyricum is -dr -1. If this province is overrun, must a dr still be made in the revenue phase to see how much the state treasury must pay?
It seems to be clearly worded, but it just seems strange that an overrun can benefit the state.
It's normal, Rome doesn't pay anymore for "poor" regions.