I noticed that the clock of my Windows 10 Desktop has been set back one hour every day I boot the system for the first time. The three possible auto-settings afaik for changing the time automatically (automatic setting of time, timezone and summer/winter offset) are off. The timezone has been set correctly during installation and I never touched it. I adjusted the time every morning for the past couple of days.
For some time I had all auto-settings on (or just the adjust time and summer/winter automatically with the timezone CET/Berlin set manually without auto-update) which didn't change the time to the correct value over days and multiple reboots.
I'm running Windows 10 in a DualBoot with Ubuntu 18.10 which has the same settings regarding time (auto-update), timezone (CET/Berlin without auto-update) and summer/winter offset (auto-update) and it works fine there.