Product Image Hover Style Unsaves

I have a WordPress account and using WooCommerce. Under the WooCommerce customisation settings I’m trying to set the Product Image Hover Style to swap images so that every time someone hovers over the product image it will show the second picture. This always used to work but now when I try to save it and refresh the page, it just unsaved itself and then goes back to ‘none’ when you select an option for Product Image Hover Style. I’ve tried the other options under Product Image Hover Style like ‘zoom’ and ‘fade’ and both work and are able to save, but just not the swap images option. What seems to be the problem here?

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