On 4/27/19 my guild and myself cleared normal Crucible of Storms fully. But for some reason half of us, myself included did not get credit for the first boss in the raid. I got the achievement for killing both bosses(I had not been in LFR so this was the first time doing them). Here is a screen shot showing I got the achievement on that day http://tinypic.com/r/34pjel2/9 But my toons armory is still showing a week later that I have only killed the last boss in the raid. Here is a link to the toon I cleared the raid with. https://worldofwarcraft.com/en-us/character/us/azshara/firesong
I am not the only member in our group that this happened to on that day. Because of this bug we also did not get the guild achievement for clearing the raid.
Many others are reporting the same issue, as am I with two of my toons. Namely the first boss of CoS Normal. Linking the other thread.