I don't understand your claim.
Why did you decide that this part is not trunk? By outward appearances, such as lines=*, surface=*, etc? The highway class defines by importance of the road. If the road is important on an international scale, this road is trunk, even if it is trash.
Shining example: Federal highway "Lena":
@Diomas/diary/13896

So, this section of road is E67? If is, then it is trunk.

source=Maaamet ortho/Maaamet hübriid