Skull markers missing in most of the Resolute area

Only one zone in the resolute region (between Vertas Pass, Superstition Canyon, Sanctus Spine, and Nightshade Pass) has a skull marker, namely Blackblade foothills. No skull markers outside Vertas pass, Sanctus Spine, or Superstition Canyon. The zones missing markers are: South Shattered Hills, Tenebris Harbor, South Broken Road, Opalis Ruins, Highvale, Middle Downs, North Hinterlands, South Hinterlands, Far Hinterlands, Northwest Blackblade Mountains, and Sunless Barrens.