Are you in Queensland and did your phone switch to daylight savings time last night?
Mine did and I am with Vaya. It's a Redmi Note 3 set to use the network time zone. Now have to manually choose Brisbane UTC +10.
I know it's happened in the past that big telcos accidentally put the whole of Queensland on the wrong time because their technician made a mistake.
Yea I did this morning as did my wife's :/
Both using the Redmi Note 3.