When saving a [.ODS] file to my networked hard drive the time shown is about 3 hours and 17 minutes behind wall time. This only seems to happen when in LibreOffice.
It is not clear from the phrase “The time shown” whether this is a reference to the Date modified timestamp on the file or date values within the spreadsheet. If the former, this may be a firmware / networking / filesystem issue, however it is difficult to tell from the limited detail in the question. Please edit the question to indicate: operating system, LO version, how the network device is accessed / mounted, file format on the network device, and your locale +/-UTC.