Removed the Rikti Warzone Mothership Rikti from the list of creatures that can be placed in missions. Any missions that specifically include these critters will now be invalid, and will have to be edited. Do NOT Unpublish your mission, or you will lose your Arc ID and ratings
From todays Patch notes. Thats likely what the problem is.
Aw man. 
Didn't even notice there was a patch today. Well, thanks for the quick answer.
"If I had Force powers, vacuum or not my cape/clothes/hair would always be blowing in the Dramatic Wind." - Tenzhi
Characters
No problem, there was an issue apparently where they were giving 2x xp.
And of course the fix goobers up the arcs that were not there to specifically farm them for the exploit.
Wait...YOU did the Welcome to Architect entertainment?
Holy cao man, that is a great arc.
Sorry to hear it (patch) flubbed one for you.
Indeed I did, heh. Glad you enjoyed it. 
And it really only affected the zone invasion mission. See, I'd put some Priests in there because of the 'hey, you usually never see these guys' feeling, and they really did make the instanced map feel like the Rikti were invading a regular zone. Without them...yeah, I'm sad because it's not the same, but I dropped some Chief Soldiers in to substitute their dialogue, and mechanically they work just as well.
"If I had Force powers, vacuum or not my cape/clothes/hair would always be blowing in the Dramatic Wind." - Tenzhi
Characters
Tried to play my Rikti arc "the Revenge of Hro'Dtohz" just a little while ago, found it invalid due to my 'custom' Rikti group suddenly having lost the 40-54 Rikti Priest. Anyone know where these guys went or why they were pulled? They were an integral part of my arc (very needed to create the proper atmosphere for the 'zone invasion' mission), and while I've fixed the arc itself, without them it's not the same.
"If I had Force powers, vacuum or not my cape/clothes/hair would always be blowing in the Dramatic Wind." - Tenzhi
Characters