I'm guessing you created the Enum on the front panel. If you right-click it and create an indicator, it will match the type, and be an enum. LabVIEW represents enums as U16, but because the types aren't identical (for example, your enum has 3 values, but a U16 has 65,536 values), LabVIEW automatically coerces (or converts) the smaller (enum) representation into the larger (U16) value.