Inline payment gateway and WooCommerce double coupon check

Hello,
We are developing a plugin for a payment gateway where the payment is not redirected to payment gateway website, but the payment takes place in a pop-up inline window. We invoke this window using the hook “woocommerce_pay_order_before_submit”. But unfortunately, it happens that WooCommerce double check the coupon. This means that if the coupon is valid for one use, the payment will not occur because it reports that the coupon has already been used. But the plugin itself does not check the coupon. This has to happen in the WooCommerce functions.

Is it possible to find somewhere what functions perform the coupon check? Alternatively, is there any way to disable the check function and then enable it again?

You can test it here:
DEMO web: https://gopay.toret.dev/ Coupon: test

Thank you.

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