Glowing sign outline doesn't change with text color when text has multiple colors

I made a sign in two different colors, one with black, one with red. The red outlined in white as if it was a black dyed sign with no color changes. it looked cool, yes. But this is an issue for people who want their signs different colors, but still glowing.

Steps to Reproduce:

1. Summon a sign that already has colored and glowing text on it by using the command provided below.

   /setblock ~ ~ ~ minecraft:oak_sign{front_text:{has_glowing_text:1b,messages:['{"text":"Line1","color":"aqua"}','{"text":"Line2","color":"red"}','{"text":"Line3","color":"light_purple"}','{"text":"Line4","color":"gold"}']}}

2. Observe the outline colors of the glowing text.
3. Take note as to whether or not glowing sign outline doesn't change with text color when text has multiple colors