Over-kneading paratha dough results in a tough and elastic dough, leading to parathas that are chewy and difficult to roll out thinly.
Kneading develops the gluten in the flour. Gluten is a protein that provides structure and elasticity to dough. When you knead dough, the gluten strands align and strengthen. For parathas, we want a moderately developed gluten structure, enough to hold the shape but not so much that it becomes overly elastic. Over-kneading causes the gluten to become too strong and tightly wound. This makes the dough resistant to stretching, resulting in parathas that shrink back when rolled, are difficult to roll thinly, and become tough and chewy after cooking. The ideal paratha dough should be smooth and pliable, but not overly elastic.
If you suspect you've over-kneaded your paratha dough, let it rest for a longer period (30-60 minutes). This allows the gluten to relax slightly, making it easier to roll out.