Placing or destroying any blocks near the Casting Basin blocks causes huge lags.
If MC's profiler is open (Shift + F3), then this gets printed in the logs:

Something's taking too long! 'root.gameRenderer.level.terrain_setup.chunk_update' took aprox 273.340704 ms

I have been unable to replicate this issue on my side. Do you know the precise conditions in which this occurs such as if the interaction occurs through a chunk boundary or if there is another mod?