Sketchup designed "Block with hole" printed solid in Cura
Problem Statement
SketchUp does not always create STLs in ways that are closed, watertight manifolds - a block with a bore is, if created as a block first and then bored out, actually 2 surfaces if made with SketchUp:

a cylinder with its normals facing inside and no top and bottom
a block that has 2 holes in opposite surfaces

The two surfaces are not connected. As a result, Cura sees two non-manifolds and tries to fix each of them - the cylinder with the normals facing inside is considered an artifact that can't be fixed, the holes in the block are stitched and thus turned into a solid block.

Fixing
To repair the issue, you could load the item into for example MeshMixer, which allows to separate and show the different surfaces (shells) and run a rather good auto-fix.
Another program that, with a little handiwork could help is blender. In blender you can first import the STL, then merge the vertices at the edge of the bore and cut cube and thus turn the two shells into one neatly, then re-export it as an STL. I strongly suggest to just add it to your Steam library if you want to keep it up to date.