Do you think there's a time and place where albinism has an advantage as well?
It's a genetic defect.
Also, evolution isn't about things being advantageous, it's about things being hereditary and not killing you before you've got babies so even if a blue lobster was something that was passed along from one generation to the next, it doesn't necessarily mean it's advantageous to the lobster, it only means that it doesn't prevent them from reproducing. We just tend to notice the genetics advantages without thinking about all the ways the animal isn't adapted to its situation.