When looking at the ghost of a vampire I threw into my fortress's volcano, I saw that they had 3,479 non-notable kills, including about 3000 humans in the town of Crownblown. Curious, I made a copy of the save, retired the fortress, and looked at the dwarf in legends. They never even went to Crownblown. I do not know what sort of bug could be causing this.

The dwarf's name is Kosoth Ginetrigòth ("Kosoth Crewcrafts"). I'm playing completely vanilla with no mods.