I am also having the same problem. When I run a balance sheet report by class, I have "not specified" even though all my transactions have a class. Even more interesting is that when I try to see which transactions QBO thinks are unclassified, it brings up all the transactions for the month. If I run the balance sheet for two months, it shows the SAME amount in "not specified" and then clicking on that line item brings up all the transactions for those two months. I've tried clearing the cache or using a different browser but still have the same issue.