Death Strike somehow synchronizes my runes and spends 4 runes per use. This is not just add-on misrepresenting runes as it can be done with all add-ons disabled.
Steps to reproduce:
Have blood spec
Go to Training Dummy
Smash target with DS and keep doing this till you are out of runes
When runes recharge next DS will spend 4 instead of 2 runes
I believe it’s just ui bug - my ui shows me that all my runes regen at the same time, while really they regen one after another (of the same type), i.e when i press the DS 2 times in row and then just watch rune regen, i’ll see that all my 4 runes get regenerated at the same time, and after that 2 of them deplete right away and regen again.
Runes regenerating one after another (of the same type) is intended mechanic.