It seems to happen in 8.1, but also earlier versions. /var/log/secure log is filled with:
/var/log/secure:Jan 14 04:02:42 citrix-olt stunnel: LOG3[3227:140623205299968]: transfer: s_poll_wait: TIMEOUTclose exceeded: closing
Note that message is repeating every 1 minute and 1 second precisely. If it's not a problem, then it should be silenced I suppose. If it's a real error, what's the issue with stunnel then?