I think I may have found a bug where readers.tindex.bounds creates an empty polygon, likely introduced around c5735c3be8 Remove pdal::gdal::Geometry (#3104). I made an issue for it at: https://github.com/PDAL/PDAL/issues/3234 I included a simple patch in the issue that fixes it for me, but I'm not sure if it is the right way to go or not.