At Novy Sobor on DayZ US Southcentral 0-6 (Experimental/Unstable) I was fooling around with a Lead pipe to see how powerful it was versus infected. After killing a second infected I suddenly get attacked by an invisible infected.
I got hit by it, could here aggro sounds (possibly coming from the dead body). A known workaround is "double tapping" the body of recently killed infected, which indeed fixed the issue.
In the Additional information section I included a video of my fight versus that infected and the issue itself and how I fixed it.