I started this topic in hope that someone will clarify something strange that happened to me yesterday while playing Skyrim. I was heading towards Ustengrav for the main quest when I decided to take care of that Hagraven at Orfan Rock and retrieve Nettlebane. On my way there I found a cave and went inside to check it out. Turned out it was filled with vampires. The weird thing is they seemed peaceful. Not even one of them attacked. I was very perplexed about it, called the situation a bug and went on my merry way without killing them.

However, I soon found myself dealing with the same thing, this time in a fortress near Falkreath, again ocupied by vampires. They just stood there, staring at me and even greeted me with "Need something", "What can I do for you" and the like. This was not a coincidence I told myself. I then remember having the "Voice of the Sky" blessing active.

So my question is: does this ability / blessing also affect vampires? If it does, was it intentional or just something the developers either didn't notice or decided not to bother fixing? Bug or is there a lore explainable behavour behind this?