Happens. Might happen in other hardware / virtualizer interaction cases.
Changing the clock behind our back might relate to kernel timekeeping issues, which can generate lots of confusion, inconvenience and even time related fingerprinting issues.
- before setting the time, store the old time in variable
- before setting the time again, check if the time matches we think it should
- if not, provide this information in a status file so sdwdate-gui can make that visible
"Clock was changed without sdwdate knowing about it. Either you manually set the time. In this case, you can ignore this. Or this is a bug." (That message can certainly be improved. We get to that once we have this feature implemented.)