Bests & Worsts Reviews from Amazon

We frequently bought this protein in the 1 and 4.5 sizes, same flavor every time (Dutch Chocolate). Typically it mixes very well in water, and you don't even need to use a protein shaker, just mix it in a cup with a fork and it mixes so well. However, with our most recent purchase of the 4.5, something has changed because on attempting to mix it, it just lumps together to form a giant glob of powder that doesn't dissolve, regardless of how long you spend mixing it. The first time I thought it was a fluke, but just tried it again for a second time, and same issue. Has something changed with the supplier/vendor? Shame, because I enjoyed this brand and not to mention dropped $60 bucks on the most recent order :(