Winbind stores kerberos tickets keyed on UID. This means that when two ssh sessions are started to a machine by the same user, both sessions share the ticket cache. When one session logs out the ticket cache is deleted leaving the other session without tickets.
I tried patching source/nsswitch/winbind_pam.c to append a random number to the ticket cache file. However, the winbind ccache is keyed on username and therefore this is insufficient. I do not have sufficient C experience to perform the modifications necessary, however, I am perfectly happy to help in any other way. Testing, etc.
I cannot verify this with neither 3.0.25c nor with 3_2 svn.
Can you describe a little more how to reproduce it (incl. your pam configuration, etc.) ?
Oh, I've just checked this again and cannot reproduce it myself either. I'm sure it was there in a previous version and I guess I must not have checked after upgrading. I'm really sorry for wasting your time on this!