Have you already bought the house and just now discovering this?

Something's sagging. The pin at the top is not stable as a permanent support. Certainly, the inspector should have mentioned it.

Agree with Worthy, something is not right there. Having a TJI floor system which in most cases designed by the manufacturer engineers it shouldn't be sagging.

I would have an engineer take a look at that.

It was done because the glams could not support the load above. The inspector did not mention it because it is obvious.

My guess is the wood I-joists were damaged by water to the point where supplemental support was required to keep the joists from totally failing. It makes me wonder what is behind the waterproofing and what the brown is on top of the waterproofing.

Then again it could be there just to take some of the bounce out of the floor.

Do you have stone or quartz countertops? Maybe it was added to provide additional support.

If the OP is a buyer, in CA, the seller may be required to disclose why this is there.