Stormwave damage goes down if strength is increased

I've encountered a bug with Stormwave where if i raise my strength by any means the damage it does appears to go down.
I can't confirm if it's only a display bug or if the damage actually goes down, but either way it's a problem.

Empty ring slot, Stormwave displays 870 DPS


Equip a ring with 14 strength and some cold resistance, no other stats, Stormwave now displays 748 DPS


The same thing happens (and with the exact same numbers) regardless of how much strength is added, confirmed this by taking a stat node to add +5 strength instead of equipping a ring with strength and got the same result, same result also if gaining strength from other gear piece, Stormwave DPS dropped to 748. The amount of strength gained doesn't seem to affect the amount the damage drops either, regardless of how much is added.

This happens regardless of level of the stormwave gem, and regardless of what gear i have equipped, in this example i'm not using any uniques, so nothing there that would cause it.

Tested on Invoker, happens at all levels of character, no skill points used that interacts with strength in any way.