Mastery: Ignite buged/denied

Heya,

Mastery: Ignite is bugged as hell and after 10 minutes of this report (http://www.warmane.com/bugtracker/report/29747) somebody denied that... Why?

Ignite should add dmg to dot by using fire spells but when you are bursting, your ignite got for example 50k dot then you use another spell and its DECREASED on 15k!?!

Basicly fire mage is loosing like 50% of his dmg when you are bursting just because of this bug..

Heres whats happening:
https://www.youtube.com/watch?v=6Ml6ip7yaZQ

I'll ask a simple question.
(Go to dummy and shoot at it with some spells that trigger Mastery)

Now tell me, what is your damage done(damage from spells, excluding Ignite) and what is Ignites damage.