No, in Season One, Amon (aka Noatok) used his bloodbending to block her bending powers, but he didn't sever the bond with her past Avatars. In Season Two, Vatu (an ancient dark spirit who possessed Korra's uncle) forcibly removes Rava (his light counterpart that's been spiritually bonded to the Avatar the past 10,000 years) from Korra and severs the link to Korra's past lives. In addition, Vatu went the extra length to destroy Rava in front of Korra's eyes, permanently ending her link to the past Avatars. By the end of their conflict, Rava got reborn within Vatu like she originally was supposed to (since they were originally the same spirit bound at the tail), Korra destroyed Vatu, and then Rava and her finally reunited; however, the reborn Rava had no attachments to the previous Avatars.