tilelive-copy hangs at minzoom of 5 or more

[bmehta]

I am using tilelive-copy to generate mbtiles. If I specify a minzoom of 5 or more, it hangs. It works fine for minzoom 4, 3, 2, 1. The mapnik xml is attached (change minzoom to whatever is passed through the CLI) and also the data file.
tracts_data.xml.zip

The tracts.sqlite
tracts.sqlite.zip
file is attached.

Hangs
./tilelive-copy bridge:////Users/mehtab/projects/mbtiles-automation/app/data/tracts_data.xml mbtiles:////Users/mehtab/projects/mbtiles-automation/app/data/tracts.mbtiles --scheme=pyramid --minzoom=5 --maxzoom=16 --bounds=-180,-85.0511,180,85.0511 --slow=1000 --timeout=120000

Does not hang
./tilelive-copy bridge:////Users/mehtab/projects/mbtiles-automation/app/data/tracts_data.xml mbtiles:////Users/mehtab/projects/mbtiles-automation/app/data/tracts.mbtiles --scheme=pyramid --minzoom=4 --maxzoom=16 --bounds=-180,-85.0511,180,85.0511 --slow=1000 --timeout=120000

Help!