This image below is from this [TI cookbook](https://www.ti.com/seclit/ml/slup113/slup113.pdf). 

Please look at the red box. 

Question: why large signal can make a conditionally stable system unstable?

[![enter image description here](https://i.stack.imgur.com/Yqg1Z.jpg)](https://i.stack.imgur.com/Yqg1Z.jpg)