Baguette blunder

So for my first-ever attempt at baking a baguette, I watched an episode of "America's Test Kitchen", downloaded the recipe, and set about reproducing the ingredients and all steps as faithfully as possible. The recipe makes four baguettes, but as I was only feeding myself and my husband, I cut the dough in half and froze one portion. The first effort was very satisfactory -- lovely deep brown crust, great crumb, outstanding flavour. The only flaw is that I have not mastered the art of scoring the dough, but that will come with practice and patience. So far, so good.

Today I decided to repeat the exercise, using the dough that I had frozen. First, I defrosted the dough in the refrigerator overnight. Then let it sit at room temperature for a couple of hours, giving it a stretch-and-fold about halfway through. Then formed the baguettes, let them rise for another hour, preheated my oven (with pizza stone) to 400 degrees (quite a new oven, and it's always been reliable, so I don't think the fault lies there). Scored the baguettes, and slid them into the hot oven. As per Test Kitchen instructions, I covered them with a double thickness of aluminum roasting pans for the initial 5 minutes,  and then removed the roasting pans. First observation: At this point, when I made the first batch the crust was starting to brown up quite nicely. Not so this time around -- bread was pale and sickly looking. So I left it to bake for another 10 minutes, then rotated them. At 10 minutes there was still no sign of browning. Another 10 minutes and the bread was kind of beige, but nothing approaching a really appetizing crust. I took them out of the oven at that point because they were certainly baked through (and my instant-read thermometer confirmed an internal temp of about 205 degrees F).  The taste is ... meh... not bad exactly, but no screaming wonder either. The crumb is pretty good, but the crust is hard (and not in a good way), pale, and thoroughly uninviting.

Any thoughts on what I might have done wrong? My best guess is that this very lean dough just does not freeze well. Other opinions and/or suggestions welcome.