Show a picture of where the crown moulding ends on the other wall so we can better advise

No crown. I'd not call any attention to it. Already looks somewhat odd.

In my opinion a beam is supposed to give the impression that it is doing something important (holding up the house), NO crown moulding.

IMO no crown .

The 'beam' is a top part of the wall after they opened up the room. If you don't crown it then you can't put it on the rest of the wall either. Do you want that wall to be the only one w/o crown? I say you continue the crown treat that 'beam' like any other wall in the room.