Dear @nirvana5,
I hope this message finds you well. We previously requested that you verify whether the issue you reported persists with the parent theme. However, we have not yet received a response from you. Could you kindly confirm if you have had the opportunity to conduct this test? If so, we would appreciate it if you could share the results with us.
Regarding your query about why the functionality works well for many items but not for others, this can often be attributed to specific code parts that may behave differently across various products. It is advisable to consult with the developers who made modifications to your child theme, as they are responsible for ensuring that the code functions correctly. If the issues are not present when using the parent theme, it suggests that the modifications in the child theme could be the cause.
For your information, the code managing variations is primarily located in the WooCommerce plugin. Specifically, you might want to examine the file located at plugins/woocommerce/client/legacy/js/frontend/add-to-cart-variation.js, which initiates most JavaScript hooks for the add-to-cart action.
Should you require further assistance with the code or need additional customization, please feel free to submit a request via our customization service at https://www.8theme.com/account/#etheme_customization_panel. Please note that such inquiries may fall outside the scope of our standard support.
Thank you for your attention to this matter. We look forward to your response.
Best Regards,
Jack Richardson
The 8Theme Team