Troy, I had a similar (the same) problem a while ago. I searched the web and asked here:
http://www.slippertalk.com/forum/showthread.php?t=28851&page=4, but I just could not find a definitive answer. I now believe (but still not sure) that it could be tissue damage from some chemical sprayed on the plant. Quite possibly an oil, but could be something else like a miticide or.....? I have looked and looked but I have never seen thrips on the leaves (even magnified) The plant almost always grows out of it. I don't seem to get it anymore since I stopped spraying pest oil.
Would love someone to prove beyond doubt what this is!