Timestamps on two cameras not in sync

I have a WyzeCamPan and a WyzeCamv3 pointed at my LitterRobot (LR) cat box, The LR threw an error this morning at around 6:12 am and it sent me a notification. I wanted to see what happened, so I pulled up the video on the v3 and saw the LR doing its thing. At 6:11:09 an LED started flashing. I checked out the WyzeCamPan. And the LED only started flashing at 6:11:13.

So the units are 4 seconds “apart” each other. I’ve done plenty of time syncs in the Wyze app for both cameras. Why do I have such a time gap?

The time does drift on the cameras and apparently, they either never check a time server, or not often enough. I have four cameras that can see me sitting here in this chair - a Pan, two V2s, and a V3. So at a known time based on a WWV based clock, I clapped my hands in view of the four cameras. Then pulled up the recordings of the four cameras. Sure enough, they all disagreed on the time by up to 7 seconds.
I don’t normally manually sync the time, and with 28 cameras, I really don’t want to need to very often!