Fix Issue 1586 - Controls are shown with error messages even if the v…

…alues are assigned

src/controls/dynamicForm/dynamicField/DynamicField.tsx

@@ -32,7 +32,7 @@ export class DynamicField extends React.Component<IDynamicFieldProps, IDynamicFi
       spfxContext: { pageContext: this.props.context.pageContext }
     });
     this.state = {
-      changedValue: props.fieldType === 'Thumbnail' ? props.fieldDefaultValue : null
+      changedValue: props.fieldDefaultValue !== undefined || props.fieldDefaultValue !== '' || props.fieldDefaultValue !== null || !this.isEmptyArray(props.fieldDefaultValue) ? props.fieldDefaultValue : null
     };
   }