Second opinion - Floor trusses and load bearing wall

Home inspector(who is also a structural engineer) said that the house had no interior load bearing walls because between the first and second floors there are floor trusses (26ft long, 20" tall, 16" o.c.).

Before knocking down the walls between the family room and living room on the first floor I decided to have a structural engineer come out and evaluate just to be safe.

He came out and immediately said that yes, the interior walls perpendicular to the trusses are load bearing because the trusses have a double vertical 2x4 right above the wall. He upsold me on drawing up a beam to replace the wall.

After he left I cut out more of the drywall to get a better look at the trusses and found that the top plate of the wall in question doesn’t make contact with the wall in question at any point along its top plate. Surely this can’t be load bearing if it’s not making contact, right? Unless the builders 20 years ago improperly built the walls and we’ve just gotten lucky I couldn’t see how they could be load bearing.

The only weird thing is that in the hallway where there is no header and no load bearing wall, there is a weird single 2x10 nailed through the 3 trusses that span the hallway area. The SE was sure this was a makeshift header since there was no wall there but to me it looks more like a place to nail the two 2x4 skirting boards that were added next to the trusses to attach the drywall.

Only able to attach one photo so I combined them. Should I be worried about taking the two walls with X’s on them down and not installing a beam? (right click and open image in new tab to view larger)

Photo notes in order:

See here the double vertical 2x4s he’s talking about. You can see the top plate of the potentially load bearing wall beneath it about 5/8" below the truss.

Back of the weird 2x10. This spans the open hallway and the double 2x4s are spaced about 6" apart so that there is room for it. Was this supposed to be a full sized, integrated header and they just cut a corner with a single 2x10 or is it a place for the ceiling drywall and 2x4’s to attach? Something else entirely?

Top plate of wall and bottom of truss with around 1/8" of space between

Top plate of wall and bottom of another truss with around 1/4" of space between

Very crude sketch of what I’m working with. Trusses run from front of house to back of house for a total span of 26ft.