Water Zone lets ocean dissapear

Hi,
I’m currently using the water system for the first time, and so far I found nothing similar in the forum.
I made a rather huge island with the Ocean Water tool.

As I understand it, the WaterZone-Actor creates high detail water in the playable area, while the majority of the ocean consists of a simplified water, that is a bit lower than the WaterZone-water.

I ran into the problem, that the WaterZone almost completely deletes the water inside its barrier. Only on the left side of the coast are a few floating water tiles. Almost everything is set to the default settings, the only real modification is the size of the WaterZone, which I had to enlarge due to the size of the map.

I probably do not understand how the water system works, but has anyone an Idea on how to get rid of this?

Thanks for the help :smiley: