The water in the bed needs to drain. If the ties were put on a few inches of gravel (below grade), that would help. Once grass is firmly established around the bed, that should help too. If not, you're getting so much water into the bed that you'll need to build a drainage system.
Off topic--have you considered that RR ties leach poisons into the soil? Maybe OK for a flower bed, but I'd think twice about using this setup for vegetables.