Subtitles text does not slowly fading out

On Java Edition, the subtitle text would slowly fading out and becoming less white, which is a great indicator of how long a subtitle has been shown to the player, this is not the case on Bedrock Edition, as the subtitle text stays white all the time.

Steps to reproduce:

1. Enable Closed Captions: Settings > Accessibility > Closed Captions

2. Go breaks a block, or do any kind of action that will causes subtitles to appear

3. Observe

Expected results:
The subtitle text slowly fading out and becoming less white, like in Java Edition.

Observed results:
The subtitle text does not slowly fading out and stays white all the time.