Shatner did ask for Nimoys consent to be part of The Captains and Nimoy said no. So Shatner sent someone to a convention to record him and ask questions. Nimoy found out and was enraged and never spoke with him again in the last 5 years of Nimoys life. Shatner revealed it himself in his 2016 book about his relationship with Nimoy. In it he still down plays it by said “it was so small”.