F70 Incorrect time stamp

I have new model F70 dash cam (no GPS option) purchased and operated in Canada.  I use a Mac desktop running MacOS Catalina 10.15.7.  Before use I updated the firmware from the Thinkware Canada site to 1.02.03 (2018-12-05).  Also updated Thinkware viewer to 1.8.6.   The Dashcam and viewer seem to work fine except the time clock does not stay accurate.  When I check views after a day or two, it's always about 3-4 hours behind.  I have reset the clock several times and "saved" in the Settings portion of the viewer (with the microUSB and adaptor plugged into the Mac and open), but the clock will not retain accurate time.   The time zone is set properly and the daylight saving box is checked.  The Dashcam is not hardwired into the car and is not continuously powered.  It stops and starts with the car using the 12v accessory as the power source.  Thanks for any assistance.