I think this was likely a case of Columbus being ambitious with their timing and things just aren't prepared yet. They claimed the new yard would be ready by the beginning of October, but it wasn't done until November. I spoke to Columbus' CEO and he was "confident" Raja would be here before the new year...while the keepers stated there wasn't a set timeline.
Columbus has technically had space for him, even before Johnson's arrival, so it's likely now a mix of crate training logistics, behavior of both herds (with a calf freshly on the ground Saint Louis might not want to risk sending a stressor through the group, How introductions between Johnson and Columbus' girls are going, etc.) and weather.