Custom fields with empty values removed completely on ajax loading of product variation

Variation that have empty field values end up completely removing the rendered field from subsequent other variations selected on the frontend.

For example, a product type called Shirt has two product variations - Blue and Green. Both variants have a custom text field called "Notes".
For the Shirt product, Green has an empty Notes field. Blue has a text value in the Notes field.
As a customer to the website, when selecting the variation from the list on the Shirt product page, the customer sees a Notes field with some text rendered (Blue is first on page load). When the customer selects Green, the Notes field disappears as expected as it has null or no value. However selecting Blue again will result in the Notes field not rendering even though there is a value in it.