Here’s what happened:
I have two partitions on my machine (currently C and D) and a USB HDD connected (F). On D and F, I have the same malware sample (one file on each drive). These paths are included in the CAV Virus Scanner Settings Exclusions. However, when scanning my registry with Comodo Registry Cleaner (CRC), the real time scanner of CAV suddenly detects the malware on F anyway. CAV obviously ignores the excluded file path and furthermore CAV offers to take action: Once again I add this malware to the exclusions, which results in a duplicate of the path in the Exclusions box.
Browsing the folder in Windows Explorer won’t cause CAV to alert, it’s just scanning with CRC. And it never happens with the malware on D (fixed HDD in the PC), it’s just on F - the external USB HDD.