Hello Dan,
Thank you for your message.
Unfortunately, modern antivirus software is incapable of distinguishing between good and bad software. They prefer to be on the safe side and block just everything which even remotely resembles an "intrusion attempt". They couldn't care less about the fact that their "detections" wreak havoc on the work and infrastructure of their own customers.
I recommend that you use
this form on the Symantec website to report the issue. We will send a false positive report through that form too. The more reports they receive the better chance that they fix this false positive issue sooner.
Let me know if you need any other assistance.