I see what you mean, the rear camera is dropping out both in normal and in parking mode
In Normal mode,The recordings for all three cameras were well behaved with 1minute consecutive loops until after 5:59 PM when all camera loops started to skip/miss recordings and the rear camera drops out.
In Parking mode, not only did the rear camera drop out at 9:36 AM, but all the recordings on June 30 are randomly skipping times and don't contain 1 minute consecutive loops
I'd try using the Cig lighter adapter for power instead of the hardwire kit for a day or two and see if it behaves. Of course you will lose parking mode.
Although I would think if it was a power problem you would have heard the camera reboot.