Detected Thread disappears

I have seen this "behavior" twice today on a new "Scan This Mac" on a a MacBookPro with a freshly installed Sophos-AntiVirus today.

The MacBookPro is running Mavericks 10.9.5 with all update current.

In one case the Malware was Mal/CryptBox-A. In this case, clicking on the "Reveal in Finder" button did not show any Path and filename" nor any information at all. The only additional information was that it said "Action Available: Restart Required". After restart, opening the Quarantine Manager showed the malware but after unlocking and clicking fon the Reveal in Finder, the file disappeared from the Quarantine Management. There is nothing in the logs about the file.

This happened a second time after the scan found another file. I did not catch the name. I clicked on "Reveal in Finder" and the Malware referenced disappeared from the Quarantine Manager.

It is easy to believe that perhaps an inexperienced user click on "Clean Up Threat" or "Clear From List". This is most definitely not the case. There is either a bug in the Quarantine Manager or perhaps the Malware is detecting Sophos and disappearing? Is that possible?

Todays experience is not the first time I have seen this behavior - things disappearing from the Quarantine Manager - but today it is pretty clear that I carefully watched and the description that people are giving is correct.

I have seen this "behavior" twice today on a new "Scan This Mac" on a a MacBookPro with a freshly installed Sophos-AntiVirus today.

The MacBookPro is running Mavericks 10.9.5 with all update current.

In one case the Malware was Mal/CryptBox-A. In this case, clicking on the "Reveal in Finder" button did not show any Path and filename" nor any information at all. The only additional information was that it said "Action Available: Restart Required". After restart, opening the Quarantine Manager showed the malware but after unlocking and clicking fon the Reveal in Finder, the file disappeared from the Quarantine Management. There is nothing in the logs about the file.

This happened a second time after the scan found another file. I did not catch the name. I clicked on "Reveal in Finder" and the Malware referenced disappeared from the Quarantine Manager.

It is easy to believe that perhaps an inexperienced user click on "Clean Up Threat" or "Clear From List". This is most definitely not the case. There is either a bug in the Quarantine Manager or perhaps the Malware is detecting Sophos and disappearing? Is that possible?

Todays experience is not the first time I have seen this behavior - things disappearing from the Quarantine Manager - but today it is pretty clear that I carefully watched and the description that people are giving is correct.