Did he apologize, and use it as a learning experience to not just blindly believe bullshit and be extra vigilant when you are spreading such bullshit to millions?
Fact checking ideally happens before you start attributing quotes to people, forming an opinion about it, and making calls to take action.
Fact checking after the falsehood has already been stated is no longer fact checking, it's simply correcting the record.
There's the famous quote: "A lie can travel halfway across the globe before the truth can even get it's pants on.". Very relevant here. He made a big deal about Biden being unfit for office, but when the record was corrected there was no mention of Trump's fitness (not to mention it being old news in the first place). The damage was done already.
MTG, Matt Gaetz, Lauren Boebert and other right wingers really don't care about being fact checked. Once their initial talking points have been spewed they move on to the other talking points because their base doesn't care about or know that the facts have been checked.
Like the clip they played of Biden, Joe and the guest believed it instantly. So I guess Joe is one of their base.