[rdonj]

The flesh ward, dimensional rod, sceptre of corruption, mage bane, gift of kurgi, the ankh, the horror harmonica, lifelong protection, soul contracts, stone spheres, and boots of the planes should all cause horror marking as well. I could have missed something, I just went through the manual for all of these.

It does seem like this is an omission from the database. I suppose if Edi notices he will probably try to add it to the next version.