Seems odd.
A box of Christmas stuff can be put behind a seat. However, as I understand it, for them to leave the space station and go back home, they need the type of spacesuits that will the vehicle they are returning on.
That is what they found when they sent a SpaceX vehicle up to get them earlier. Their spacesuits weren’t compatible with Musk’s ship.
So, I reckon that they are waiting for the suits that do fit Musk’s ship. Something like this.