Tracking cookies, I don't even waste my time scanning for them in SAS, they aren't a security risk, but if anything a minor privacy risk and shouldn't slow any connection.
As for any detections with SAS, if they haven't been detected by avast you can send the sample to avast before allowing SAS to quarantine and delete it, improving detections for all avast users.
e.g. Send the sample to virus@avast.com zipped and password protected with the password in email body and undetected malware 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.
It may be no bad thing to confirm the detection at virustotal.