You were using split text on same elements multiple times, which was creating nodes as many levels deep. In the loop, on first tween you are setting opacity and in next two tweens you are setting color but not opacity. So lets say your animation completed till 3rd line, now all character nodes in first 3 lines have opacity 1 but rest of the lines have opacity 0. Now when you click again, split text is creating new character nodes 1 level deep. First 3 lines will work fine because their parent has opacity of 1 but rest won't show up because their parent have opacity 0. If you were using opacity everywhere it would have worked, but wouldn't have been efficient.
I will suggest reading this article to better plan your animations,