Gnus: Buffer has a running process; kill it? (y or n)

[白い熊]

When I run the current CVS version of Emacs and connect to my IMAP mail server 
with Gnus, I get a message on startup:

Buffer has a running process; kill it? (y or n) 

When answering y, for every Gnus instance you run you end up with one hanging 
process, and when exiting Emacs after
closing Gnus you get the prompt:

Active processes exist; kill them and exit anyway? (y or n) 

and *Process List* shows:

imap<1> run      (Killed) gnutls-cli -s xxxx.xxxx.xxx -p 143

one line for each process.

*Messages* shows:

imap: Connecting to xxxx.xxxx.xxx...
Waiting for response from xxxx.xxxx.xxx...done
imap: Reconnecting with stream `starttls'...
Opening STARTTLS connection to `xxxx.xxxx.xxx:143'...
Buffer has a running process; kill it? (y or n) 
imap: Reconnecting with stream `starttls'...failed
imap: Connecting to xxxx.xxxx.xxx...done

If answering n to the prompt to kill the active process, everything is the 
same, just upon Emacs exit *Process List* shows:

imap<1> run      *temp* gnutls-cli -s xxxx.xxxx.xxx -p 143

for each hanging process of each Gnus instance started in the Emacs session.

When running Ubuntu's emacs-snapshot, which is of version 20090320, *Messages* 
shows the following:

imap: Connecting to xxxx.xxxx.xxx...
Waiting for response from xxxx.xxxx.xxx...done
imap: Reconnecting with stream `starttls'...
Opening STARTTLS connection to `xxxx.xxxx.xxx:143'...
imap: Reconnecting with stream `starttls'...failed
imap: Connecting to xxxx.xxxx.xxx...done

but no message on startup and there is no process hanging on exit. So something 
is also failing, but no processes
hanging remain.

How can I fix this?

Best regards,

白い熊