TEPCO reported that cooling to unit 3 was interrupted on December 5:
Associated Press. December 5, 2016. Fukushima reactor briefly loses cooling during inspection. The Asahi Shimbun, http://www.asahi.com/ajw/articles/AJ201612050069.htmlHere is a screenshot from TEPCO webcam 1 that shows a plume of something coming up from unit 3. That something was perhaps a little worse than ordinary on December 5 but it hasn't looked good since the ice wall was reported as failing.
One of the melted reactors at tsunami-hit Fukushima nuclear power plant had a temporary loss of cooling when a worker accidentally bumped a switch while passing through a narrow aisle of switch panels during an inspection and turned off the pumping system. The plant operator, Tokyo Electric Power Co., said cooling for the No. 3 reactor, one of the three reactors that melted following the 2011 earthquake and tsunami, was out for nearly one hour Monday until a backup pump kicked in.