[Psitticine]

Somebody's definitely messing with you. Check the list of global spells to see what's been cast. There is one (Purgatory) that causes strikes against undead within dominion friendly to the caster of the spell.

Oh, and Soul Gate works best with a high dominion. The higher your dominion in a province, the better your free summons are. Some of the best units need to be manually summoned, but they are amazing. Nothing like an immortal undead spell-caster to ruin a Jotun's day!