Procedural marble texture not working in 2.81 onwards

[Tedri_Mark]

I’ve got a procedural texture which works fine in 2.80:

But has this weird blocky look in 2.81a onwards:

Any ideas why?

Here’s a simple blend:
Marble.blend (1015.8 KB)

Thanks in advance

[Tedri_Mark]

EDIT: If I unplug the normal from the principled BSDF then the blocky look disappears, but then of course I just have a smooth material.

This is the final procedural texture that’s driving the bump node:

If I unplug that, and add a simple noise texture, the bump map works as I’d expect.

Puzzling…

[Tedri_Mark]

Okay it gets weirder:

If I use a mix RGB node to mix between the generated texture and a plain grey, and set the mix just to the plain grey, the bump disappears as expected, but the block artifacts on the colour are still there:

[CarlG]

I’d need to spend more time with it, but it seems to only happen to such an extent in Eevee. Must be something going on with the fake blur (which I highly recommend not using for bump anyway) and the custom generators. Using either in bump works, but it fails even when using 0 fac RGB mixing. I’m guessing at some point there is garbage collected in one of the channels.

[Tedri_Mark]

Yes it’s very strange especially the the bump affecting the color even when it’s turned down to zero…

@CarlG

Must be something going on with the fake blur

Yes I do wish there was a real blur node available.

Thanks for having a look for me!