When playing with the Dynamic Traits submod and the Scavenging Skill mod, it's possible to not earn Grave Robber when you should. If you meet the skill level requirement before the kill requirement, you won't earn Grave Robber until you reload the game or level up Scavenging again. If you reach max level scavenging before fulfilling the kill requirement (which is easy with the Skill Recovery Journal mod), the only way to gain Grave Robber is to reload the game.
When playing with the Dynamic Traits submod and the Scavenging Skill mod, it's possible to not earn Grave Robber when you should. If you meet the skill level requirement before the kill requirement, you won't earn Grave Robber until you reload the game or level up Scavenging again. If you reach max level scavenging before fulfilling the kill requirement (which is easy with the Skill Recovery Journal mod), the only way to gain Grave Robber is to reload the game.