[imp] Encrypted mail in sent foöder not readable

[Jens Grüntjes]

Hello list,

I send a pgp-encrypted mail from my address jens.gruentjes at domain.tld  
(managed by horde) to myself at jens.gruentjes at domain.tld (not managed  
by horde). Both addresses use the same PGP-key. When I look at the  
mail in the sent-folder in horde I get this error:

The data in this part has been encrypted via PGP.
The data in this part does not appear to be a valid PGP encrypted  
message. Error:Could not decrypt PGP data.

When I open the mail in another mail client (KMail) and enter the  
passphrase the message is properly displayed.

The same error occurs when I send a mail to a different person.

I've read about similar errors in the mailing list and bugtracker  
(#4332 or #11085) but I did not a find a solution for my problem. Can  
somebody help me to find what is going wrong?

Greetings
Jens