I have taken a look at this title by opening a copy in Motion.
As it is now, it won't work in a vertical project. The position of the bubble is controlled by a rig - more specifically, a pop-up menu, with the options "Upper Right", "Upper Left", "Lower Right" or "Lower Left".
This pop-up controls how the speech buble is positioned onscreen. As it is now, its location ends up being outside the frame if the project is vertical. Since the position is rigged to this pop-up, you cannot manually change it in FCP.
One way to make it work would be to make a copy - call it, say, "Speech Bubbles (vertical)" and adjust the position and scale of the bubbles determined by each setting of the pop-up.