msi file built in Jenkins sometimes gets detected as trojan as sometimes not

Question

I have a problem with a C# application built inside the Jenkins Build Environment of my company: the application sometimes is detected as trojan and sometimes not.
After I build this C# application, I always scan it with VirusTotal. Sometimes the application gets detected as Trojan:Win32/Wacatac.C!ml or as Program:Win32/Wacapew.C!ml, and sometimes not.
What is really strange for me, is the fact that the two same msi files, built from the exactly same source code, without any change between one build and the next one, one time is detected as trojan and the next time not.
I'm 100% sure that the detection is a false positive. But why there's this different behaviour? The problem is on the Jenkins side or on the scan side?