Hi, if a user goes to a different page or closes a tab, there shouldn't be any new 404 errors related to the previously viewed page as a browser terminates the current page "session" and starts with a new one. License.lic is not saved across these pages "sessions" (no cookies, local storage, etc).
Do you have more details about the issue or possibly send us a link so we can reproduce. You can send it to support at webrotate360 dot com.