For a few weeks now in EV we have not received credit in the 16-man for killing Soa. We did KP on a different day with 8 and received credit without issue.

Is this a bug and we're just not receiving credit because of it, or are we being forced to do the 8-man to progress our 16-man?

We'll be mixing it up and heading into KP next to see if the others will receive credit for their quest in the 16-man, so I guess it remains to be seen.