I am very sure. A quick Google search doesn't turn it up, so I think it must have been in the early part of Four Steps to the Epiphany. My copy of that is in storage, though, so I can't find the quote. You can see similar sentiments here: http://steveblank.com/2010/10/04/why-pioneers-are-the-ones-w...
Sorry, I'm referring to this paragraph: "They guess at their business model and then do premature, loud and aggressive Public Relations hype and early company launches and quickly burn through their cash. This is a great strategy if there’s a bubble occuring in your market or you are going to bet it all on flipping your company for a sale."
This still doesn't say "ignore all the Lean startup advice during a bubble". That's what you claimed, and this sentence doesn't say anything of that sort.
He is saying that in a bubble it is a great strategy if you "guess at their business model and then do premature, loud and aggressive Public Relations hype and early company launches and quickly burn through their cash."
That is precisely the opposite of the Lean Startup approach. So I believe the sentiment is, as I said, similar. If you aren't seeing that, I'm happy to disagree.