Subtitles don't fade out with colored text

If a subtitle has colored text, it will disappear abruptly instead of fading out.

Steps to Reproduce:
1. Enable the Resource Pack (Options > Resource Packs > Drag and drop this file: MC-269043.zip)
2. Enable subtitles (Options > Accessibility Settings > Show Subtitles: ON)
3. Drop an item
4. Pick it up
Check if the text in the subtitles fade out correctly.

What I expected to happen was...:
Both normal text and text with a set color fade out

What actually happened was...:
Text without color faded gradually, while text with color disappeared abruptly