Brian here from PreSonus. I have created a support ticket for you and it should be in your account. If you are having a problem submitting a support ticket, please try using Google Chrome as your web browser. You can then log into your my.presonus.com account and click on "Support" to submit a ticket.
If this is an issue with file associations on your computer, please right-click one of the files and choose the option to "Open With." You can then check the box to always use the selected program and choose Notion 6.
If there is a problem with the actual files themselves, we would have to take a look at one. You can just attach it to your ticket that we created for you.
More than likely, this is a false positive, but it is hard to say without more information. If it is a false positive, you will want to release the file from the quarantine. We can talk about that in your ticket. I have not heard of BitDefender having a problem with any Notion files in the past. When you get a chance, please reply to your support ticket and we would be happy to assist.