Summon Harbinger of the Arcane tooltip is incorrect

The tooltip of "Summon Harbinger of the Arcane" states "Summons an immortal harbinger minion. The minion will occasionally cast Arcane Surge on you, granting more spell damage and increased mana regeneration"

That is cool and all, and inline with the old Arcane Surge, HOWEVER the buff granted states that it grants cast speed and nothing about more spell damage.

Evaluating my states, I also only recieves cast speed.

I assume, that someone simple forgot to CTRL + F -> "arcane surge" in the code base to find this, but it would be super cool, if this specific Arcane surge granted by the harbinger was special and granted more spell damage instead of cast speed, but it is kinda useless with an attack triggered spell, which the weapon also grants.