Do nail binders rest only in the middle, unstable?

Hello dear forum community,

we recently bought an old house and are currently renovating.

Our carpenter pointed out to us that he believes something is wrong with the nailed trusses because they apparently rest "only" in the middle and are not connected to each other.

He says the entire construction works under compression and tension and the trusses should be continuously connected in the middle; however, he has never seen such a construction before.

It even looks as if the trusses were neatly separated afterwards.

In the last photo, you can clearly see that the beam is split in the middle. Although a board was nailed on both the right and left sides, the entire beam is still split in the middle.

I would almost say that someone nailed it together and that might have been wrong, and in the end it was split again!? Unfortunately, we don't know anyone who is familiar with this construction method ;-((( The question is simply whether this is correct or if we should connect the beams in the middle afterwards (they are split in the middle throughout the entire house from front to back).