I'm beginning to wonder if this is a device failure. I have a GW1100 as well and that's fine so there was no power issue at year end.
Stuart
I have 4 GW1000s , all with the correct date set for year, all running the latest firmware. However, I did have one that did not reset.
Because these were bought at various times, I have no clue if it was a hardware version or something else, or maybe, how it detects the "new year", and if it misses it and goes on. Again no idea