I believe that the Prologue added a couple new missions, where Thrall can get some extra levels and gear while the player learns some mission types like map exploration and hold-out. When I completed the last Prologue mission, Thrall was level 4 or 5 and had a full list of items.
When I start the first Orc campaign mission, Thrall is back to level 1 and all items are missing. There is also a message that appears showing that the Troll Headhunter is a new unit, even though I had already acquired and used them in the previous Prologue missions.
This can only be a bug, as I cannot believe that Thrall spent time forgetting his experience and tossing his new items overboard during the trip West. Why even add so much extra content, items, and stat bonuses (from the library area) if it’s all going to be taken away?
Maybe this is just a small oversight, but I really hope it’s fixed eventually, as it takes away from the game immersion. Please fix!