Due to how Stadium update has been implemented, it gets in the way of a specific danger sign aimed at stadium. As a result, you can’t land in the middle of the stadium since you hit an invisible wall that stretches FAR outside of the newly added “waves” (decorative walls). See screenshots for details:
A fix would either remove these walls entirely, or lower them to the height of the extra stadium walls added in the latest update.
PS: they also work as invisible floor, although they block you in the area above stadium, with the only way out being fast travel.