The background of the title text does not fade with the text

The Bug

The background of the title text does not fade with the text (when Text background opacity is enabled (= not set to 0%) in the accessibility settings menu).

How to reproduce

Type the following commands in order and by enabling (= not set to 0%) and disabling (= set to 0%) the background opacity of the text in the accessibility options (or set "Text Background" on "Everywhere" and "Chat"):

/title @a times 70 10 70
/title @a title "Test"

Example

Here is an example in video: