Please find the images as below.

1. figure from CFD post. (Screenshot of CFD post)


Zoomed image 1 (Screenshot of CFD post)


Zoomed image 2 (Screenshot of CFD post)

But when I save it as an image, I am getting the colours right as shown below. Could you please let me know the issue. Why am I getting multiple colours in CFD post? 


I think this is the issue with graphic card rendering. But I am amazed because I am using 4GB Nvidia GeForce GTX 1650. 

Your help is appreciated.