Have you sent the file for analysis and correction, if you don't do that they won't know. That is how the other FP was corrected so quickly.
Send the sample to virus@avast.com zipped and password protected with the password in email body and false positive in the subject.
Or you can also 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.