Man that is strange, and also a shitty deal if you are tryin to up your protien intake. I have used all kinds and usually try something new after every batch. I will tell you that although the isolates are much better protien source, they are way worse tasting! Make sure you have a concentrate.
My advice to you is ... drown out the taste! You may not be getting as much protien per shake, but you will just have to take a few more per day. If it is a chocolate shake ... try this ... buy nestle quick mix, and dump in a shit load of more chocolate flavour! (shitty for cals though). Like wise for vinnalla, add vinalla extract ... it does not take much of this as it is very strong to add extra flavour in your shake .. its cheap too. For straberry, add strawberyy koolaid mix, or real fresh strawberries, and try also adding ice cubes, so they crush up like a smoothie! This is very good and is what i do as a ice cool drink goes down much better than a warm one. Make sure you use a blender and don`t mix the shit in a glass, as it may say it does on the label, but the shit doesnt ... much better in a blender! Hope this helps .. good luck bro! If all else fails, you can buy premade whey drinks, such as isopure etc. Very good, but verey expensive as well!
Good Luck,
Mavy