Some injection methods are detected because of memory writing. Virusses mostly edit the underlaying memory, and your virusscanner will check it and probably give you a detection message due to the pattern matching.
Apart from the injector, the hack could cause an alert too. This is because of the hack using some methods that the virusscanner can not accept.
We could say those virusalters are false positives but hey im not the expert, just a thought!!