Bizarre audio feedback bug

Very infrequently, when I port back into an area, my character will exclaim the kill-a-champion speech; on my Templar, this is of course "Go with God!". He says this immediately upon entering an area in which I surely have killed a champion, only that was usually minutes ago when in the aftermath I cleaned up, gathered loot, and ported to town. The delay of a few minutes, triggered by the re-port into the area, makes it quite eerie.