Opening Vibrant Visuals will make text on signs with colors become black

When a world opens Vibrant Visuals, text on signs with colors will become black.

Steps to reproduce: (Make sure Vibrant Visuals is closed firstly)

1. Create a world.

2. Place a sign (any kind) anywhere, and input "§etext" in it. You will see the text is yellow.

3. Quit the world, open Vibrant Visuals, and reload the world.

Expected result:

The text is still yellow, like that without Vibrant Visuals.

Actual result:

The text becomes black.

This bug not only influences yellow color, but also influences other colors.

The two pictures in the attachment were taken at the same place, within the same text on the same sign. You can see how Vibrant Visuals influence the color of the text.