I ran a duplicate computers by serial number custom report and then looked up the serial number in the console to delete the duplicate however when I checked the console did not display 2 computers. I then deleted the computer in the console (because it was an old one and likely not coming back after a month of inactivity as well as not being pingable). After that I searched for the computer by serial number in web reports and it still shows one computer even though it no longer exists in the console.
What would cause this behavior and is there a workaround to remove this computer from web reports?
Edit: I answered my own question and removed it using the computer removal tool.