AVG does not appear to delete a quarantined file on a USB drive

Greetings,

This isn't the usual behavior of AVG. However, we'd  like to clarify this for you.
From your description, we see that the action to be taken against threat is set to 'Move to quarantine' in AVG & 'delete automatically' in Malwarebytes.
Hence, this has happened. However, if a file is moved to quarantine by AVG, then the same file shouldn't be moved again in the subsequent scan.
This can happen if the file differs. As we're uncertain about the exact file, we'd suggest you to continue using AVG & in future, if you experience the same issue with any other file, please reach us initially.
We'd be glad to investigate further on it & help you. Thank you for your understanding in advance!

An infected USB stick was scanned recently with AVG's free Windows anti-virus software and a malicious item was placed in quarantine (looked like the recycler folder on the stick). I then manually deleted this from the quarantine using the AVG program. When I reran AVG, however, the virus reappeared in the quarantine. Re-running the process did not clear the issue. As a test, Malwarebytes was run against the stick, located the virus in the recycler bin, and deleted the file. A subsequent scan of the USB by AVG showed no sign of the virus. Comments please.

Thank you for explaining. 
Would you be so kind to let us know if the file is still available on the USB stick? If so, please rescan it using AVG to regenerate the issue & share us the screenshots of the quarantine, threat detection for better clarity.

Thank you for the response, Dinesh.
The issue is one of perceived deletion by AVG. Although the file (see below) was deleted manually from within the AVG program, it reappeared in the quarantine on the subsequent scan. Only by removing this rogue file via Malwarebytes did AVG eventually give the stick a clean bill of health. By the way, the computer hosting AVG and Malwarebytes (not the real-time monitoring version) did not itself contain any viruses.
The virus was Win32:MalPack-E[Tri] and resided on the USB drive as d:\Recycler.…\winfixer.exe

Greetings,

This isn't the usual behavior of AVG. However, we'd  like to clarify this for you.
From your description, we see that the action to be taken against threat is set to 'Move to quarantine' in AVG & 'delete automatically' in Malwarebytes.
Hence, this has happened. However, if a file is moved to quarantine by AVG, then the same file shouldn't be moved again in the subsequent scan.
This can happen if the file differs. As we're uncertain about the exact file, we'd suggest you to continue using AVG & in future, if you experience the same issue with any other file, please reach us initially.
We'd be glad to investigate further on it & help you. Thank you for your understanding in advance!