Here's what one of Bernie's comms people tweeted then deleted after Biden's campaign went at Bernie two hours ago. Looks like the apology was bait and then kept the focus on SS.
I get the tendency to armchair coach this campaign cause I know I'm emotionally invested in this but it looks like they played this pretty well. Corruption is a strong word and while I think Biden is corrupt, it can be seen as a negative within the context of this election due to Trump and the impeachment trial. Social security is a specific issue that can knock over Biden.