It is most certainly an FP, the file last modified date doesn't have to be later than when you enabled SR, it is independent of SR as it relates to the original files last modified date, which could also pre-date the installation of AIM6.
Send the sample to virus@avast.com zipped and password protected with the password in email body, a link to this topic might help and false positive in the subject.
Or you can also add the file to the User Files (File, Add) section of the avast chest (if it isn't already there) where it can do no harm and send it from there (select the file, right click, email to Alwil Software). No need to zip and PW protect when the sample is sent from chest. A copy of the file/s will remain in the original location, so any further action you take can remove that.
For it to be in the C:\System Volume Information" folder, it would have had to have been previously moved/deleted from on of the system folders.