Subtitle Problem

So I'm currently using command blocks to make a Puzzle Map called "The Brain" and I'm using the new Subtitles and Titles but after you've used a subtle once the subtitle doesnt show up afterward unless you refresh the map. Like even if I try to make a new subtitle none are showing up. I know I'm using the right command because it works if I put Title in it but not subtitle. Please fix this so I can release my map soon. Thank you.