Selecting a certain text on a caption changes its color to default black.

I work on captions as the screenshot wherein a part of the phrase has a different color. Now, when I close it and reopen the captions and then select the color picker, while changing nothing at all, it will revert back to black. You see I have some words that are colored yellow, once I go back to those text, and then get the color picker to copy the color (because I intend to copy the color to be used in other text) the color goes back to black even if I didn't change anything.