Why is the Pururava pastime told partially in the ninth canto and then later completeted in the eleventh canto?

From: SCCD

In your wonderful lecture titled  “Realization comes by moving up and down the ladder of abstraction – Pururava song analysis ” you said Pururava section is left in between in 9th Canto then continued in 11th canto. is there any specific reason for this?