Altering color via custom BBCode causes pixel font to render incorrectly

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:bust_in_silhouette: Asked By SpaceAttorney

I have a custom BBCode effect for my dialogue that changes the color of certain snippets of text based on their context, seen below:

@tool
class_name BBCodePaint
extends RichTextEffect

var bbcode = "paint"

## Internal dictionary of paint tags and their default color associations.
var tags : Dictionary = {
	"default": Color("#1a1817"),
	"thought": Color("#4d4a49"),
}

func _process_custom_fx(char_fx):
	# Grab tag, if applicable.
	var tag = char_fx.env.get("tag", "default")
	
	if tags.has(tag):
		char_fx.color = tags[tag]
		return true
	else:
		return false

(for those wondering, the reason I’m using this and not the normal [color] tag is so I can change the context/color mappings in this script and have all dialogue update automatically)

The problem is that when I use this code in a RichTextLabel, the font starts to render incorrectly. Here is a comparison of the results, compared to the results when I just use the [color] tag to change to the same color:

Custom BBCode dialogue
Standard BBCode dialogue

This doesn’t occur if I use the engine’s default font. It also didn’t occur in Godot 3 when I used the same code with the same pixel font.