Payment Page Discount Not Working

Hello, I have been using BOGO+ on my site for 8 months. But today I’m having a problem. When users add the product to the cart, a BOGO popup appears on the screen and they add the discounted product via the popup. However, the discount suddenly disappears on the payment page. I am sending you the screen recording.

https://drive.google.com/file/d/1IifgkGkJIcsVViu-WPPi7labnMigubki/view?usp=drive_web

Which BOGO+ app do you use for your site? You should contact the support team of the app’s developer, and they will help you solve the problem.