I am experiencing that colors are not consistent across gamma.
There is a slight increase in saturation once rendered compared to the color that is visible in the IOBox.
Also when exporting a PNG sequence yesterday that I needed to process in Davinci Resolve, I noticed the colors were way off, previously setting the input colorspace to sRGB was fine, now I needed to set it to linear.
SceneWindow and SceneTexture nodes both have an input called “Enable Default Post FX” which is true to optimize for a default of working with the high-level physically-based-rendering workflow. if you’re not using this, turn it off and you should see your colors as expected.