The base color of a PBR material is inconsistent depending on whether it's opaque or alpha blended: in opaque mode, the base color's low end is crushed in a way that's consistent with a lossy sRGB-linear conversion, whereas in blend mode it is not.

Steps to reproduce:

1) Rez 2 cubes

2) Apply this material by UUID on both cubes: 4123dd84-6f3e-52d0-4f8d-051d7c1a7c20

3) Set Scaling to U 0.125, V 1.0, offests U 0.24, V 0.0 to zoom into the gradient's dark end

4) Observe the intense banding at the dark end of the gradient's colors

5) Set one of the cubes into alpha blend mode instead of opaque

6) Observe that the banding disappears and the texture is displayed correctly wrt. the actual colors in the base color layer

7) Bonus: rez yet another cube, apply this texture as Blinn-Phong diffuse: bf0a0a57-8574-3f55-b5bc-eaae688b181e

8) Set scale H 0.125, offset H -0.2 to zoom into a similar region as the PBR material

9) Observe there is no banding, looking quite identical to the alpha blended PBR

Demo image has opaque cube on left, blended cube on right.