Every object in scene has the same material... but some have slightly different tints?

As the title says, some objects in my scene have different colors.... even if they have the same material.

When Im building something... I start with primitives.

I placed multiple cubes and scaled them accordingly.

In this image, I have 4 cubes and a floor plane all using the same material.

The 2 skinny planks both have a pale red color.

Heres the same scene but with actual colors on the blocks themselves: