Redirection to admin interface after payment

[snipymc]

Hello,

I'm having problems processing payments with Mollie and returning to my website. Instead of landing on the order overview page, I am redirected to the wp-admin page.

The link looks something like this:
https://domain.tld/shop/kasse/order-received/8445/?key=wc_order_KfxB41cQlnaD9&order_id=8445&filter_flag=onMollieReturn

If the GET variable "&filter_flag=onMollieReturn" is removed, I land on the order overview page, if it is attached - as specified by the plugin - a redirect to the wp-admin page is carried out.

How can I remove this variable when returning from Mollie to my website so that the order overview is loaded or how do I fix the problem that there is no redirection to the admin area when the variable is attached?

Thank's a lot!