THREE Drain Vitality shouts?!

[Valden21]

Yep, I have THREE Drain Vitality shouts. One of them is the real shout,the second one looks like it's the glitched version, and the third seems to be the same of the glitched one, but with a shorter duration. How could I have gotten that third one, and could it cause any problems for me in the future?

[cfs111]

Learning a word of Marked for Death after having installed Dawnguard causes a glitched shout to appear in the Shouts menu. It is named Drain Vitality, but has all three words of Marked for Death. The recharge is 12,12,12 and the bugged description says "Drains x points of Health per second for 20 seconds. Drains x points of Magicka per second for 20 seconds. Drains x points of stamina per second for 20 seconds." Using the shout causes the effect listed - although no words are actually shouted by the character. NPCs do not become hostile.

This bug is fixed by version 1.1.2 of the Unofficial Dawnguard Patch.

Learning the Drain Vitality shouts will then result in a second Drain Vitality shout, consisting of the right words of power, appearing in your Shout list. Also, if you obtained the location of this shout via the Greybeards, the quest will not update upon learning the Drain Vitality Shout and you will be unable to learn new shouts from the Greybeards.

To fix this bug open the console and type in the following command: player.removeshout xx018244 for the 1 point version or player.removeshout xx0181b8 for the 2 point version or player.removeshout xx0181b7 for the 3 point version. Also see Form ID for more information on the xx.

A way to fix either bug above is to perform the following steps:
1.Find a save in which you have not learned any words of Marked for Death and have not started the Dawnguard questline.
2.Delete/uninstall Dawnguard.
3.Load up the save and get all three words for Marked for Death.
4.Reinstall/re-download Dawnguard.

From: http://www.uesp.net/wiki/Skyrim:Drain_Vitality

[Solomon Hawk]

That glitch has happened to me consitently since installing Dawnguard quite some time ago.
I eventually got to the point when I see it on a wall, I'll learn the word, but won't activate it.
I've yet to use the console command to remove it.
The one at Archwind Point is inexplicably tied to another word wall elsewhere and if you're sent there by the Graybeards, it won't complete until the shout is learned at the other wall.
Have to avoid going to that wall before I pick up the quest to Archwind Point from the Graybeards. It's a painintheass.