@SSpE 

Did you set up Auto rebooting schedule? I did see 1970 on log but that only happens after a rebooting of the router. It's reasonable, after rebooting the router needs some time to sync time

  @Somnus 

I was not aware that the ER605 had the auto reboot feature.

If it does and not set by default, I have not scheduled one.

Thanks for the date stamp information. That bit of time travel had me thinking buggy firmware.

Just yesterday my 2nd ER605 did the same thing.

Side note:

The original router in question also will not automatically update time/date information no matter what time server I choose, using either global or IP address. This causing it to stay dated in 2018, until manually update, unlike the 2nd that will automatically update time from 1970, 2018 to the present.

Both routers are on battery backup power supples, so now curious as to what would cause the rebooting, if not power failures.

Still waiting to hear back from TP-Link engineers.

  @SSpE 

You can try the Omada Controller.

That will force the router to use the same time as the controller, so I only need to confirm the controller has a correct time.

  @Somnus 

Thank you for the reply.

My question is more , why the constant resetting log back to 1970 then to current day.

No one is rebooting, there have been no power outages and thew routers are on backup power supplies as well. 

One router I use global name for NTP server, but the other I have to use the IP address for it to connect and get the correct time.

Both units are using the same provider.

Trying to get cable company back out to make some repairs, so I am not ruling that out.