Tracking popup doesn't work anymore in the backend

[TimQSO]

Magento 2.3.3

On the frontend the tracking popup of an order works for customers. However, when a employee wants to track and order it does not work, because the store_code includes the website_code.

Sales -> Shipments -> Shipment -> Click the barcode number of the shipment.

It will open a popup like this:

https://www.mywebsite.com/mysite_nl/shipping/tracking/popup

While this should be

https://www.mywebsite.com/nl/shipping/tracking/popup

Nginx workaround for this issue:

location /mysite_nl/ {
    rewrite ^/mysite_nl/(.*)$ $scheme://$host/nl/$1 permanent;
}