Product Options Checkbox adding to cart regardless of checked

-- HikaShop version -- : 6.5.0
-- Joomla version -- : 5.4.7
-- PHP version -- : 8.4.23

Hello, I'm running into a strange issue on two sites that have a few products with an option set under Specifications. I have Display > Product Options > Product Selection Method set to "checkbox," and the option is added to the cart regardless of whether it's checked on the product page. Changing this setting to "single dropdown" seems to clear the issue and functions as intended. I can also uncheck the option in the cart's edit screen to remove it.

I'm wondering if the checkbox on the cart's edit screen defaults to "checked" regardless of the customer's choice, but I'm not 100% certain. I also switched to the Cassiopeia template to rule out Gantry and the Chimera theme, but got the same result.

Any help would be greatly appreciated. Thank you!