I have the exact same issue. No clear solution. Sometimes I fixed it by moving the river a bit on the X axis and then undoing. After a couple of seconds the water appears again. But I feel this works 70% of the time.
I have the exact same issue. No clear solution. Sometimes I fixed it by moving the river a bit on the X axis and then undoing. After a couple of seconds the water appears again. But I feel this works 70% of the time.