Am I dumb or is it a bug?

Hi guys, I'm pretty new to World of Warcraft, and I started leveling a sub rogue, but I noticed some strange patterns. Whenever I use my ability ,,Ambush'' I gain two combo points (as intended) but damage dealt to an enemy by ambush disappears after one or two seconds, and my target is full hp again. Am I dumb and I don't completely understand how ambush works, or is it a bug?

I am not playing Mop but the Creature shouldnt heal as long it doesnt reset. For example if you vanish the creature will reset and gain full hp again. If thats not the case than the Creature is properly bugged and you should skip it. If this occurs for other creatures too, than the aability it self is the problem. I can only advise you to test it on other creatures and make an report with screenshots on the bug tracker.

I hope i was able to help you.

That's because you're using Subterfuge. When an NPC has no target, it resets. The bug exists since Day 1 of MoP on Warmane and I doubt they will ever fix it.

Thanks for replies, but what should I do? Should I unlearn subterfuge and take another talent instead, or just level up without my ambush?