Hello! I was hoping I could get some advice about my Sony A7r lll. I bought it a couple weeks ago and I am concerned there may be something wrong with it. It is a certified refurbished unit and it only had 1 picture taken according to the shutter count.
 
QUESTION 1
I shoot RAW (ARW) & JPG simultaneously and I am noticing a lot of bright random colored pixels in all my RAW images, but not in my JPG images. I would assume this is just noise from using higher ISO (about 4000-5000 ISO) but I would think I should see the same thing in my JPG images. I have attached some comparisons. You will notice that the ARW images look darker, more saturated, and they have terrible noise, accompanied with random colored pixels. 
 
QUESTION 2
I also feel and hear something moving in my camera body if I slightly shake the camera. Is this just a byproduct of having in-body image stabilization?
 
QUESTION 3
I was shooting some video today and I noticed subtle horizontal banding in my display and the recorded video (seen in the last image/screenshot circled in red). The banding travels upwards. Settings are listed below..

• File Format: XAVC S HD
• Record Setting: 30p 50m - Changing this didn't help
• Silent Shooting: Off - Changing this didn't help
• e-Front Curtain Shutter: On - Changing this didn't help
• Anti-flicker Shoot - Changing this didn't help

 
This one is especially odd since I have shot both photo and video in the same conditions previously, with no issues. Now I cant do anything to get rid of this banding. This happens in auto for photo mode and video mode. I suspect I may have changed a setting somewhere without realizing it, which is causing this problem.
 
Are these signs that I got a faulty unit or are these things normal? Thanks in advance!

 

Q1

The difference between RAW and Jpeg is that RAW data has had no processing done to it - allowing full control of the editing to you, whereas Jpeg has some processing done in-camera, which often gives a more pleasing photo than a non-edited RAW image but does not allow as much scope for you when you edit on a computer. Effectively you have handed over some of the processing to an algorithm written in some far off computer. You will see how much smaller a Jpeg file is to the RAW file, which gives an indication of how much information has been lost.

Most people who like their photos "out-of-camera" will shoot Jpeg - those who like full control of the creative process shoot RAW. Those who like a back up shoot both.

Q2

The noise from shaking your camera could well be the few moving parts, including IBIS.

Q3

I don't shoot video.

So, as far as stills photography is concerned, I would offer you reassurance that your camera is good.

I concur with @thebeardedgroundsmans answers. What's more, a high megapixel sensor like in the A7RIII will show more noise on pixel level than an A7III (24MP) or the A7S (12MP).

Regarding the banding in movies: what shutter speed did you use? A shutter speed close to the frequency of artificial lighting will cause banding in the footage.

All in all, nothing wrong with your camera I'd say.

Banding due to artificial lighting. You'll never see it in daylight.