Other than the original 6.8 release version 3.6.23-33, samba has not been functioning correctly for me under 6.8.
The symptoms are that about 6-7 days after starting the server, users start complaining that they can no longer open documents on their share. Upon inspection, I find several, sometimes nearly a dozen smb processes owned by a single user, on top of those run under root. Stopping the service does not stop these processes. They are only killable with SIGKILL, and after that, a service restart does not result in a functioning service, i.e. connections are refused, which can be verified easily with smbclient. The only cure is a server reboot. And it is not the same user id every time it happens. Useful logs of any type are not available.
I have tested -35 and -36, both show the same behaviour. This is a production server and I have no time for tinkering; downgrading to -33 and blocking samba updates is the only workaround for now.