KDE SC 4.9.5 and KMail issues

[Diederik de Haas <didi.debian@cknow.org>]

Since both Reinhold and Benjamin confirmed the issue I have with KMail [1] since 
the upgrade to 4.9.5, the next step is identifying the cause and finding a 
solution to it.

Summary:
Settings on the Advanced tab of an Identity's Settings (Sent/Drafts folder) are 
not retained when you (try to) change them. I have mostly Disconnected IMAP 
accounts, but it also happens on a POP3 account I have.

Problem is that I have to clue how to 'debug' the issue.
Pointers?

Cheers,
  Diederik

[1] http://lists.debian.org/debian-kde/2013/01/msg00066.html