It started happening around the time of the 4.4 patch. I don't remember if it happened before it, but this has been a recent thing and it's been extremely annoying to my raid group during progression. As far as I know, I did not do any PC updates, I have my windows firewall disabled as well. As for where in game does this happen, it happens anywhere. Inside instances, inside my house, out in cities, or out in the field. The constant that it always happens every two hours.