According to the Scotts rep. and the MSDS, the organic choice contains peat and manure both of which have a decent amount of variation potential. It contains anywhere from 10 to 25% manure and peat moss (5-15 and 5-10 respectively). I'm thinking it was probably a high cow manure content and somewhat lacking quality control from a batch that resulted in bugs and a high amount of peat that led to a larger-than-normal pH swing/drop. I'm no expert or anything but it seems like all the QQ is a bit overblown. Also, they do not recommend the product for use in aquaria, stating that it can lead to algae and cloudiness issues.
I love the stuff and will keep using it. Just takes slightly more effort.
Also, there are two types of the same product (garden soil) on their site but they are listed as separate products. One even has a warning on it not to be used by children and suggests the use of gardening gloves. Peculiar. Assuming both of these products are available for sale in addition to their potting mix, I think people may confuse the various types of soil. The bugs I still think are a bad batch.