I deleted all but 3 from my app and then updated a couple times in Illustrator and it seems to be working correctly now. I'll try using it a couple more times to see if it behaves and will repost with the result.
Ok, I've logged in and out, created new themes and deleted them several times in the last day and all seems to be working fine now.
My thought is this was a one-time anomaly; when this happened, I had just upgraded to Adobe CC, installed updates and new programs, installed the Kuler App, created a new Adobe account, etc...maybe a bit too much activity all at once?
All is good now. Thanks Shamit_Mehta for the offer to clean the themes--it did take a little while to do that! ;-)