Hello, Parshva
1/ We recommend disabling the WooCommerce Infinite Scroll and Ajax Pagination plugin or setting the correct settings, as outlined in the following article: https://xstore.helpscoutdocs.com/article/65-woocommerce-infinite-scroll-and-ajax-pagination-settings/.
2/ Sales Booster > Fake Sale Popup > Elements > make sure that Location is enabled, or provide temporary wp-admin access, so we can take a closer look at your settings.
3/ Theme Options > Speed optimization > Menu Dropdown Ajax Loading > Off.
4/ Please post your question about multiple purchases via form tact form on this page – https://themeforest.net/user/8theme
Kind Regards,
8theme team