Inverting Luminosity of texture produces artifacts.

Steps to reproduce

Reproduce the bug in papers:

1. Open and run this papers fork: GNOME/Incubator/papers!380
2. Switch to Night Mode on a document containing text.
3. Zoom into text.

Reproduce the bug in gtk4-node-editor:

1. Open the attached Blend.node render node file in gkt4-node-editor using the vulkan or ngl renderers.

I haven't written too much GTK C code yet, so I don't have minimal C reproducer yet. Would a Rust + gtk-rs reproducer for building a widget with a custom snapshot also be accepted here?

Current behavior

A high resolution "color"-blend of a texture with it's inverted version produces render artifacts on the unified renderer (ngl or vulkan).

Expected outcome

No artifacts.

Version information

I'm using GTK 4.17 from the the org.gnome.Platform:master flatpak runtime.

Additional information

See GNOME/Incubator/papers!380 (comment 2281683)

Example Render Node: Blend.node