I was messing around with possible multiclass from Warlock and had only selected a few Domain cards, but when adding the Warrior Slayer at level 6, I saw that the Blighting Strike L1 Dread Domain card was reading as magic damage of 3d6+7. To confirm that this was the issue, I removed the multiclass and saw it drop back to 3d6+1. Based on the listing for the feature, it should only add character level to physical damage. Not sure if the error is on the card or the feature.