What are the rules for upper circuit in index options?

I am currently selling FinNifty options.

I sold FINNifty 20400 CE & PE. Upper circuit circuit for CE is showing 590.45 and for PE it is showing 711.7

My questions are:

1.) How long will the upper circuit last, before it is revised and increased?

2.) No matter what, will the upper circuit always hit & pause trading for X minutes? Even if FinNifty spot shoots up 10% in 1 second?

I remember during freak trades in 2021 or 2022, the upper circuit was not working, why was that?