According to the docs, I set UV1 to (3,2,1) for CubeMesh node and tried to apply the same texture on all 6 faces. It has no problem if I use image texture, but if I use Viewport texture, the behavior is strange.
Here is the screenshot when I use viewport texture. The viewport contains a ColorRect and painting with a single line canvas shader code.
Here is the screenshot if I use image texture
Since I only change the texture, I expects to see the similar result (same texture on all faces). But it is not the case.
Here is a simple Godot project shows how to reproduce the problem. I also wrote some detail steps for how to reproduce it in README.md.
Is it a bug?