Samples should be sent directly to avast and not post links to enable people to download the undetected sample as you have no control over who downloads it or what they might do with it. Please remove the file sharing link.
Send the sample to virus (at) avast (dot) com zipped and password protected with the password in email body, a link to this topic might help and false positive/undetected malware in the subject.
Or
Send the sample/s to avast as a Undetected Malware:
Open the chest and right click in the Chest and select Add, navigate to where you have the sample and add it to the chest (see image). Once in the chest, right click on the file and select 'Submit to virus lab...' complete the form and submit, the file will be uploaded during the next update.