Broken gnus-posting-styles?

[Philip Kaludercic]

(I'm posting here because I don't have anything concrete enough for a
bug report)

Is anyone else tracking master and experiencing issues with
`gnus-posting-styles'?  I read my mail via nnimap, and had it set up so
that it Gcc's outgoing mail into my Sent directory.  As I have two
addresses I use, I sed `gnus-posting-styles' to

      '(((header "from" "fau.de^")
         ("Gcc" "nnimap+faumail.fau.de:Sent")
         (address "cuvyvc.xnyhqrepvp@snh.qr"))  ;Anti-spam
        (""                                     ;Fallback
         ("Gcc" "nnimap+posteo.de:Sent")))

But for some reason the "(header ...)" doesn't work anymore, and all my
messages are stored in the "Sent" directory of my primary account.  If I
invert the rule, I get the opposite behaviour.  Yet `(gnus) Posting
Styles' indicates that that this approach should work.

Anyone know what is going on?