Title commands not working with subtitles

Title commands that have subtitles are no longer showing up with other titles:

As an example, I would have two command blocks, one with /title @a title Hello, then i would have /title @a subtitle world, so usually it should display a title hello with the subtitle world, however it is only showing the title and not the subtitle - what is weird is that this command seems to be working for another player on the world with the exact same command format