That isn't true, unfortunately. Google don't give out a specific number, although this Matt Cutts Video [youtube.com] suggests "one, two or maybe 3" redirects would be fine, "4 or 5" not fine.
You're still wise to go for one hop, but I don't think this would explain all of the issues you're seeing. Remember that Penguin is an 'anti-spam' update, so that wouldn't correlate either, even if the 1 redirect only rule was accurate.
[edited by: Andy_Langton at 4:37 pm (utc) on Feb 26, 2013]