Poet's Pen dual wielding dps tooltip

The tooltip dps of poet's pen seems to be wrong while dual wielding. I get about double dps on the tooltip of my Kinetic Blast when equipping a second poet's pen. As I understand it the added physical damage should be a local modifier, but it seems to be calculated as global. The actual damage does not feel at all close to double so I think it's just the tooltip that is calculated wrongly somehow.

It's the same with Elemental Hit as well, but even more a differance (about tripple while dual wielding).

I am a witch if that matters somehow.

Screenshot of chat:
https://gyazo.com/51bda792a689a13ce8e500f6cea0be33
Bug report reference number: 119 269 314