Is Starbucks' New Vivanno Kosher?

Last month, Starbucks launched a new beverage, Vivanno™ nourishing blends. There are two flavors currently available: orange mango banana and banana chocolate. According to their press release,

With customers looking for healthier options to fit their on-the-go lifestyles, the new Vivanno™ beverage line is one way Starbucks is meeting requests for great-tasting, good-for-you offerings while furthering its commitment to food and beverage selections that support a healthy lifestyle. The simple ingredient list for both beverages includes:
• one whole banana,
• a proprietary whey protein and fiber powder,
• choice of milk,
• and ice (in the Orange Mango Banana Blend, Naked® Juice is also added).

This is certainly an interesting move, especially for those trying to get more protein into their diet. However, the question is, "Are they kosher?" So, to this end, I e-mailed Starbucks' customer relations and Madeline responded "Due to the nature of your inquiry, we are unable to provide an ideal response via email. Therefore, we would like the opportunity to provide/gather more information in order to best assist you. Please call our customer relations department at 1-800-235-2883." So, today, I called.
A nice, young lady named Kate answered my questions (Starbucks' customer relations, if you are reading this, she did an excellent job). Kate said that the protein powder is a proprietary blend certified by the Kof-K. However, she said that the Naked juice in the orange mango banana blend is not certified kosher. This strikes me as strange since the OU says Naked juice is kosher. Anyways, in the orange mango banana blend, aside from the Naked juice and the proprietary protein blend, there is also water and milk. In the chocolate banana blend, aside from the proprietary protein blend, there is milk, water, banana, and mocha sauce (the mocha sauce, according to Kate, is certified kosher by the OU).
Of course, at the beginning of the call, Kate gave a general kosher disclaimer that Starbucks uses non-kosher products behind the counter and that none of the stores are certified as kosher, per se (even though there are many products that are kosher).
Anyways, while searching for my answer to the original question, I came across KosherStarbucks.com that says "The Orange Mango Banana, and Chocolate Banana Vivanno are kosher only without the Protein & Fiber Powder. You must specify each time you order that the Protein & Fiber powder should not be included in your beverage." This statement seems bizarre to me if the Kof-K says that the protein and fiber powder is kosher.
Anyways, I don't know / caveat emptor.