Well one strange thing about your recipe is that it asks specifically for a low protein flour. The baguette recipes I have seen asked specifically for bread flour, which is high protein. I can't see why you would use a low protein flour for a baguette, or for any bread, for that matter. I don't know how, if at all, this connects to the yeasty flavor, but it's something to consider. Perhaps you should get a different recipe.
As for instant yeast, if you intend to substitute active dry, the correct ratio is 3 AD for 2 instant. (You do the math) However, I have worked with instant yeast, and I don't believe this is likely to be your problem. May I ask, how much are you proofing your bread? If you allow it to rise too much, the flavor will definitely be affected.