OS: Windows 10 Pro 22H2 19045.4355
Fences: 5.04
Unable to provide a video.
This is the desktop before the URLs fence is unrolled. Notice that paint.net icon is spaced three spaces down from top of screen.

Now with the URLs fence unrolled I click on & drag 'fullstory Website Monitoring' icon towards taskbar (so that it becomes pinned item on Firefox). Notice that this icon is also 3 spaces down from top of screen (& so overlaps with paint.net icon shown in previous screenshot.
When I drag the URL icon off of the bottom of the URL fence, the item the cursor has selected suddenly changes into paint.net

I hope that I have been able to explain the issue clearly.
Regards, Mark.