An item Quaratined does not appear in the Quarantined window

This is the second time this has happened. I received a popup saying that a file has been Quarantined yet, when I opened the Quarantined window, there are no quarantined files to view/remove, etc. What could cause this?

Thanks

Are you using Comodo Firewall or Comodo Internet Security? What version are you using?

Internet Security V 5.12.256249.2599

Do you have another scanner running at the same time? May be that could have caught it.