If I understood your reply correctly, you refrigerated the dough balls for about 24 hours and let them sit at room temperature for about 2 hours before using.
Based on that understanding, my best diagnosis is that your dough was not sufficiently fermented. Jeff says that the dough balls should be kept in the refrigerator from 1 to 6 days. One day, or even something a little longer, may not have been enough. It is also possible that your starter was not active enough. If that was the case, you would have ended up with a dough that would not risen much even under the best of circumstances. But even if the starter was active enough, and even with the addition of 0.294% IDY (by weight of flour), it would not have been unusual for the dough not to rise that much during the cold fermentation period you used. In all likelihood, the dough balls rose but you may not have been able to detect it. Often the dough balls slump and flatten into a disk-shaped mass, making it difficult to tell visually whether they really rose. If you had allowed the dough balls to rise several hours longer at room temperature, I believe you would have seen the IDY kick in and cause the dough to rise very noticeably--not double or anything like that but perhaps by 25-50%. At that point, the dough would have been soft enough to handle. If you re-kneaded the dough balls before shaping and stretching, that could well have contributed to the "buckiness" of the dough you experienced. But even if you didn't go overboard with the re-kneading, if the dough was underfermented to begin with, that condition would also have manifested itself by buckiness in the dough.
Using a thermometer is always a good idea although I don't think that would have mattered much if the dough didn't receive adequate fermentation and was on the stiff side.