Just to clarify, it's not the prompt voodoo that caused the affinity for goblins. It's the reward. They rewarded it for mentioning goblins when set to Nerdy, and it's still the same model as the other personalities, so the effects can carry over.
TL;DR the cringe nerdy shit should be (optionally) switched on at inference, not as part of RL
As the article says, the personalities weren't supposed to affect other personalities. OpenAI was as surprised by the goblins as you are. Training can be tricky.