It was told by Snoop and them that Pac did roll up on Nas and them. That story was repeated by multiple people who were there, including Jungle. edit: the first time
But before he passed it was rumored that after that particular incident he had planned on removing the disses to Nas. But he didn't do it in time. Not because Nas had threatened him but because he liked his music. Atleast that's what I read. Pac was too live and affiliated as it is for it to be otherwise. And that's not speculation, that's a fact
And instead of using Nas' name he just would've dubbed it over with Pras. That way he wouldn't have had to change shyt. Which would've made sense at the time. Because truthfully, he was doing what 50 did when he first came to Aftermath