Lately, My SmartThings hub has been losing connection to my TCP hub, which controls my lights.
It’s happened several times in the last week, and overnight the last 2 nights.
It might have been happening more than I was aware of, because the lights weren’t dimming reliably due to another bug (http://community.smartthings.com/t/scheduler-quits-after-some-minutes-hours-or-days ), for which I recently implemented a workaround.
The only way I have found to reconnect (temporarily) to the TCP hub is:
On my cell phone app, I go to SmartThings Labs -> Tcp Bulbs.
On the Connect your TCP Lights to SmartThings page, my username and password are already entered. I click Next, then Done. It seems to work for 1-4 days after this.