UV Mapping is not preserved correctly for faces where the texture is
applied using the Paint Bucket tool and not not positioned or projected.
This happens when the faces are within a group or component that does not
align to the world axis.
The issue is also seen when you explode the group / component. This is a
SketchUp bug / limitation which can only be addressed by SketchUp itself.
Bugs
Insert Vertex occasionally creates new faces when there are holes in the
face. Investigating.