I would suggest that is a question for military intelligence. The degree to which they were in a position to overtake the country was something that took, I think, everybody by surprise. On the timing, certainly ADM Thoppil may have more to say about this.
The speed with which the U.S. departure from Afghanistan converted into a situation where the Taliban were in control surprised, I think, the entire world. I won't go so far as to say it also surprised the Taliban, but I don't think any of us would have predicted an August fall of Kabul.