Is there any official ruling on how objective allies are controlled during quests like Conflict at the Carrock?

Does Grimbeorn move with the first player token like Frodo does in the campaign expansion?

As I understand it, all the allies that say "The first player gains control of ..." switch every turn. I don't think Grimbeorn does, for no particular reason I can understand.

Celador and the rangers from Into Ithilien don't switch, because they go to the first player as a one-off When Revealed action.

Here are a few threads with answers regarding control of objective allies:

https://community.fantasyflightgames.com/topic/101806-the-first-player-gains-control-of/?hl=grimbeorn

https://community.fantasyflightgames.com/topic/77580-grimbeorn-vs-arwen-and-wilyador/?hl=grimbeorn

You may be able to find the designer ruling in here somewhere (I don't have time to look):

http://www.cardgamedb.com/forums/index.php?/topic/1702-official-nate-rule-clarifications/ or in Alogos's helpful unofficial FAQ compilation document ( https://docs.google.com/document/d/18_pYjnXi27r1P886cMHGmb7ZX-tuWeTLe7bGIVP-vs4/edit?pli=1 ).%C2'>