Yes, that's possible. Clocks on Agent machines should always be kept in sync with the clock on the Server machine. Setting up NTP is probably the best way to go.
You should not expect anything to work properly without your machines having their clocks properly synced.
See our install docs here:
where it says:
All Jopr Servers and Agents must have synchronized clocks. Clock variations will cause issues in resource synchronization, availability reporting, measurement collections and data, graphing, and importing resources into inventory. Refer to http://www.ntp.org/ for information on installing and configuring NTP to ensure your clocks are synchronized.