Update: Looks like Barret Zoph, GPT-4's post training (co-)lead is also leaving: https://x.com/barret_zoph/status/1839095143397515452
Probably with some form of NDA attached.
As LLM capabilities start to plateau, everyone with any sort of name recognition is scrambling to ride the hype to a big pay day before reality catches up with marketing.
I do think that whoever Bob is, they probably really are a good manager. EDIT: I guess that's Bob McGrew, head of research, who is now also leaving.
I'm not sure why the HN algorithm never let it hit the front page, but there's discussion here: