I tested around with Bolt Staff on Battle Wizard and found something strange.
The damage dealt by my fully charged attack with Volcanic Force was roughly 17% higher in the keep compared to a mission. All tested on spawned enemies, not dummies.
This 17% difference stays the same across enemies and appears even without any bonus power from anything else to influence the calculation. No power versus, no enhanced power. It might only happen on armored enemies though.
I’m not sure what else it applied to because the weird behaviour doesn’t end there. I restarted the game, and now the difference doesn’t appear anymore. The damage is the same in keep and mission. HOWEVER, the damage increase from volcanic force is now roughly 44% instead of 50%, everywhere!
Other players could reproduce these incorrect numbers so it’s not just some odd result of how my game is set up.
None of this makes sense. Please look into what could be going on with the volcanic force talent to mess with the numbers to this extent.