Me too facing the same issue also reported it to sony service but they told it was my router problem but even if i connect to my neighbor router same issue.Not even a month now bought this TV sony technician visited 3 times now and still issue isn't solved.But when the TV is connected to a mobile hotspot the date wont reset only connecting it to the router and powering it off it changes to default time 5.30 and date 1/1/2015. Even the Sony senior engineer that was sent was not able to solve the issue feels like cheated by Sony.
Sony many of them are facing the issue and we are been told when sked for help that it is a faulty router or local internet provider.No proper help is provided.Now since my no. is registered with service centre they no more send any help even after 3 visits are done by sony technician .Is this what i get from a well known brand? Today when called the sony service centre he simply hung the call on me.Teerible service