Incorrect (nonexistent) tiles at zoom level 11

[Iancam]

Using this geoJson at zoom level 11

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "coordinates": [
          [-107.57474911721675, 37.765903789097095],
          [-107.57384175953081, 37.75616186145916],
          [-107.50425513238076, 37.71049221239559],
          [-107.4731808734297, 37.62036834873592],
          [-107.47599073203504, 37.61112403824043],
          [-107.47295160433036, 37.599860534562524],
          [-107.45664930903803, 37.59101553690758],
          [-107.44956219593156, 37.56375515522157],
          [-107.4410913786216, 37.55329488693623],
          [-107.44463546019313, 37.54102064839029],
          [-107.44368651302858, 37.50716987497118],
          [-107.43132230490518, 37.497378059487716]
        ],
        "type": "LineString"
      }
    }
  ]
}

I should be getting something around [412, 792, 11] according to what the tile. Instead I'm getting [ [ 240, 1286, 11 ], [ 240, 1386, 11 ], [ 240, 1486, 11 ] ].

[Iancam]

It appears that the issue is coming from the toID and fromID functions, as the coordinates in lineCover look correct. I converted toID and fromID to use strings and I'm getting correct, though probably slower, output.