Mortars -- What is going on?

So I got a pretty weird set up here or something, because I’m getting insane damage ranges with my Pit Lord who has 5% more damage for every 1%, in tandem with Mortar Combat, so in theory this should be beast, and it is – sometimes.

Sometimes I’ll hit for 52 damage to all enemies, and other times for 3000! And in either case, I’m attacking a mortally wounded Dead type. I understand my damage is spread across all enemies, but jesus, am I doing anywhere from 400 - 9k single target damage?

Anyone want to weigh in on this mystery? I don’t know if this is an issue here, but I figure there’s some mechanic or invisible math here I’m not getting. It seems like Pit Lord’s attack stat is largely ignored and all of their damage is based on enemy health remaining, when I would’ve thought it’d work more as a bonus.

Contradiction affects Mortar Combat, but the damage discrepancy is probably because the damage is based on the target you select when you attack. Keep in mind that all damage dealt by this ability is considered indirect damage, so post-attack abilities will not activate from any attacks made by creatures with Mortar Combat.