ACF does not save both the value and the label of values in a select field, it only saves the value. ACF depends on the field settings when returning the label and gets them from the $field[‘choices’] setting. For ACF to return the labels that are different from the values you would need to permanently update the field settings for the field.
In this case you would have to use an acf/format_value filter to change the label returned by ACF.
