In the attached save, there is a pond zone ready to be filled (Elevation 10 next to the trading depot). In the 50.08 beta, the dwarves who get assigned the 'fill pond' task stand next to the well in the hospital (same level, lower right side) in the state 'hauling bucket' forever until they get dehydrated or hungry enough for them ditch the job. Without the beta, the pond is filled as expected.