Pretty handy bug happened both myself and my brother tonight in the exact same general area in Chaos Wastes. Would be great for people levelling or doing PQ's here to have the level 36 bolster buff.
Not 100% sure on the exact trigger for this, but it shouldn't be too hard to reproduce I don't think.
Happened to my brother when he flew in from Inevitable City to the "Seven Shades Creep" Warcamp in Chaos Wastes. He then mounted and went up towards Deathchill. Somewhere along the lines he received the Bolster buff as he was level 30, which boosted him to level 36.
About an hour later, I, also, was running from the "Seven Shades Creep" Warcamp up to Deathchill to hand in some quests and the same happened to me. Level 31 bolstered to 36 outside of RvR zone.
Try it out, see if it works for you guys. I don't have time to go through the nitty gritty of it again as I'm done with that area, but maybe someone could post up if it was useful for them.
EDIT: Seems that it's happening nearly everytime I go into Seven Shades Creep warcamp. Once you receive Bolster you should keep it (even if you die) as long as you don't change zone via flightmaster etc.