I had this problem last week with my game too
Please login to see this link.
I submitted a couple of reports- I found that it was actually flagging anything I compiled with fusion too, so I sent them a couple of examples.
My game's exe was also too big to send so I uploaded it to dropbox and sent them a file link via email.
During that time it was a panic as I had a decent chunk of users being told it was a virus. Potentially it's very damaging to reputations, and I'm still pretty worried it's going to happen again at some point.
The good news is that it seemed to stop flagging my game after about 24-36 hours- somebody at avast must of took notice. If this is still happening to people though, maybe they just added my game to a whitelist somewhere and haven't actually fixed the detection (or maybe my game will start getting flagged again soon, yay )
Seems like Avast are quite aggressive with their detections (I read they have more false positives than any other AV). Still, it's one of the biggest AVs, especially as it's free. Aside from sending them false positives there's not much we can do. Clickteam- I'd suggest reaching out to them too perhaps, if you haven't already? I know we shouldn't have to, but if fusion gets a reputation for triggering false positives, it's going to be a red flag against it for developers