What is the avqmd.plist and the _avqmd record in Users/Groups
You might be able to get some more details on the user by querying your directory database rather than looking at the record files on the filesystem:

dscl . -read /Users/_avqmd


Hopefully you'll find enough threads to pull on. It's not an account on any of the first few Macs I checked, but perhaps someone else has tracked it down already and has a more concrete answer.