WowAce

Rarity doesn't seem to be tracking Soundless (and maybe other 8.2 rare) kills properly. I've killed Soundless almost every day since 8.2 came out and on some days even killed it on alts. Yet Rarity says I have 10 kills. 

My guess would be it's not tracking kills made while in a raid group?

This is not what I'm observing. I've only managed a few kills because it's pretty difficult to find, but all of them have been tracked properly, including those in a raid group that I opened. Rarity only cares about you looting the NPC, so whenever you do an attempt is being added.

I think it's not picking it up if I use the Loot-A-Rang. Tried looting it manually today and that increased the count in Rarity. 

I'm not sure about that either, I remember using my Loot-a-rang just yesterday and the attempt definitely counted. I'd have to try again and pay more attention to be certain, though.

Unless I can reliably reproduce the problem, I don't know how I should go about fixing it :)

I'm not a 100% sure that's the issue. But it's no big deal, you can close the ticket if you want :)

I can't reproduce the problem, not even with a loot-a-rang. All my 15 attempts so far have been tracked, and I always open a raid group to invite others as well.

If you've any more information I will be happy to look into it, but until then I can't do much :)