Unexpected GET call in php file

When running an HTML file with in MS Edge on Windows 10 in the Replit Web IDE and using the GET-Method, the content of the connected php-file isn’t displayed correctly. It disappears after one second and in the console you can see, that a GET-Method is called, which actually shouldn’t be called, because it doesn’t exist. But if you open the project in a new tab, it all works correctly.