I can confirm that we’ve reproduced the issue, and we will be looking into it.
The background for the issue seems to be very complex and irregular geometry of some of the objects in the scene. It seems Shapespark has difficulties to properly unwrap them to produce lightmap UV mapping.
Are some of the objects coming from a CAD application? Cleaning/optimizing such objects in the 3D modelling tool could work around this issue. Optimizing them may be helpful anyway, as many of them have high polygon count making the scene total to 7M polygons, which is too much for mobile devices or older computers.