There are repeated rumours that failed explosives were found at the site.
https://www.eugyppius.com/p/nord-stream-update-the-recovered
Holger Stark, the German investigative journalist who broke this story for Die Zeit. Stark has apparently told Hersh that “Officials in Germany, Sweden, and Denmark … decided shortly after the pipeline bombings to send teams to the site to recover the one mine that has not gone off”. He said they were too late; an American ship had sped to the site within a day or two and recovered the mine and other materials
They did however recover a smoke buoy
https://www.eugyppius.com/p/nord-stream-update-the-recovered