I see an overwrite feature under settings for pdrI noticed my rear view vibrates quite a lot, too. I only notice it when using "real" mirror mode.
I could be wrong, but I don't think the PDR will overwrite. Once it fills up, assuming you have it on automatic recording, it will just tell you the card is full. Surround view will overwrite the oldest video. With a 128GB card, it's still a ton of video.