Since v.1.6.0 of the module, we have added the ability to exclude GET parameters from Redirect URLs. Please note that the Exclude GET Parameters from Redirect URL feature is available only as a part of an active product or support subscription. You can find the amasty/module-geoip-redirect-subscription-functionality package for installation in composer suggest.

The functionality could be enabled in Stores → Configuration → Amasty Extensions → Geo IP Redirect:

Once the setting is enabled, the get parameter would be excluded during redirect: