No, because he never said it directly just hinted at it:

• Biden Suggests He Would Only Serve One Term if Elected President

Asked in October if he would only serve one term if elected, the former vice president told the Associated Press that he wouldn’t make that promise but he wasn’t deeply committed to seeking a second term.

“I feel good and all I can say is, watch me, you’ll see,” Biden said. “It doesn’t mean I would run a second term. I’m not going to make that judgment at this moment.”

However there were several advisors on his campaign that said it:

“If Biden is elected, he’s going to be 82 years old in four years and he won’t be running for reelection,” a prominent adviser to the campaign told Politico.

In private? I can see them saying it on TV and the rubes still voting for them since all they watch is Fox News and they’d never run it.