You can see that the artboard on the left is a shade of grey, whereas the one on the right is slightly bluer. What gives? What am I missing? Thank you so much in advance! Any ideas much appreciated!
They are the same.
It's an optical illusion due to the gradient and the UI coloring.... Which is why I stick to the Light UI coloring.
That's the right side overlaid on the left side.. there's no edge showing any color variation.
When you are uncertain about this, it's a simple matter to select the object and check the Color Panel for the numbers used. If they are the same... it's an illusion. You can also use the Info Panel to just hover your cursor over various areas and see the numbers related to the color breakout to verify they are the same.