Over-kneading chapati dough results in tough, elastic chapatis that are difficult to roll out and may shrink back after rolling. This is because excessive kneading develops too much gluten.
Chapati dough requires kneading to develop gluten, which provides structure and elasticity. However, over-kneading leads to excessive gluten development. This makes the dough overly elastic and resistant to stretching. When you try to roll it out, it will constantly spring back, making it difficult to achieve a thin, even circle. Furthermore, the resulting chapatis will be tough and chewy, rather than soft and pliable. The ideal kneading time for chapati dough is typically around 5-7 minutes. You're looking for a smooth, elastic dough that is soft to the touch, but not sticky.
If you suspect you've over-kneaded your chapati dough, let it rest for at least 30 minutes before rolling. This allows the gluten to relax slightly, making the dough more manageable.