Your browser is set to open an internal home page that does not display anything in the URL window, that window is blank.
You have policy exclusions to ignore file transfers to the URL of that home page.
Those exclusions do not work, the agent does detect the transfer and creates an incident.
And you see an "Unknown URL" in the incident.
If you open a new tab and manually enter the URL of the home page, the exclusions will work when transferring data using that tab.
No incident will be created.
Our agent extension collects the URL from the URL window when the page/tab is opened.
If the page loads without a URL in the window, then our agent will not have any URL data for the policy rules to check.
And you will see the "Unknown URL" in the incident.
There is no workaround.