WowAce

What steps will reproduce the problem?
1. Use common Arcane build (57/3/11)
2. Draenei race (have not tested other races)

What is the expected output? What do you see instead?
Spell damage bonus from intellect is greater than what is expected.  87 intellect is expected to give [0.15*(87*1.15) = 15.0] spell damage.  The tool tip lists 15.5 spell damage.  All items experience this 2.7 to 2.8% inflation in spell damage from intellect.  Furthermore, the summary section at the bottom of the tooltip is also inflating the total spell damage by 2.7 to 2.8%.  Consider the trinket, embrace of the spider (+98 spell damage).  The summation at the bottom of the tooltip list 100.8 spell damage.  As expected, removing the trinket reduces the spell damage shown in the character window by 98 and not by 100/101. Switching to Deep Fire build (20/51/00) corrects the error in the summary stats (i.e., trinket spell damage summation is 98).

What version of the product are you using?
1.4.6

Do you have an error log of what happened?
None generated.

Please provide any additional information below.

Follow up information: 1. Does not appear to be due to an addon conflict as I have tested with all other addons disabled. 2. As additional confirmation of the summary stat inflation for spell damage, I summed all the listed spell damage bonuses from ratingbuster. The summed value was 3% greater than the spell damage total listed in the WoW character window,

Mage: Arcane Instability (Rank 3) - 1,17
Increases your spell damage and critical strike chance by 1%/2%/3%.

So this does not increase the spell power stat?

I don't believe so.

The current tool tip states "Increases the damage done by your spells and your critical strike chance by 3%"

I believe this talent acts like a modifier for calculated spell damage (similar to the Fire Power talent) instead of the spell power stat. The data from the trinket above is consistent with this (i.e., the character sheet only shows a delta of 98 spell power when removed and not a delta of [98*1.03]. The mind mastery talent does increase the spell power stat.

Based on some comments on WoWiki, it appears that the tooltip description was recently reworded (to what I listed below) to clarify the intent of the talent.

Arcane Instability is removed from LibStatLogic r76, which will fix your problem :)