Hello there @Anonymous_d61fbdbb28ddee46718a7ebe5b8748f3 !
That’s quite a particular isssue you are facing, as the build was baking with no problems before adding the third river, which suggest that everything should be fine with your setup and the plugin itself. It’s more likely that the additional water body is having a faulty interaction, somewhere in your scene.
Looking around the community, the closest scenario I could find was combining a river with shallow water, resulting in failure to render. Please check if their methods of resolution can work in your scene:
For further actions, we will need to know the specific error you are getting on the failed bake. Is there a log or crash report you can share here?