Water Body River & World Partition

Hey,
So I was following this Tutorial here: Tutorial

I’d love to use the baked River Simulation in my project. However, I’m having trouble getting the standard water body river to work in my project. If I try to drag it in, this happens:

The Flow is wrong, the River does not affect the landscape. Even if I adjust the Water Zone, nothing happens.

Is it still broken with WP? Or am I missing something here. Thanks in advance!

Cheers