First I just want to say if the store had already had 8 complaints why didn't they pull all the bags off the shelf....why would they keep possibly bad stock around for others to buy!
I think the complaints were all made on the same day as I rang up, but don't quote me on that.

it IS a clear plastic bag...Didn't anyone take the .. oh, I dont know... 2-3 seconds to look at the treats?
My sister bought the bag, I don't know why she didn't notice, probably too distracted by the bunnies or something In her defence the moldy ones were mainly in the middle of the bag (that first pic is the actual bag with the moldy treats in, and as you can see they look ok from the outside) but still, I'm surprised not only she, but the people who work there, didn't notice, you'd have thought whoever stacked the shelves would have seen it