Hilbert key error

fail.txt

java.lang.IllegalArgumentException: bitSetRange=Pow2LengthBitSetRange[start=size: 4096 bitset: {},level=4096] exceeds 62 bits for a non-negative long.
[info]   at com.google.common.base.Preconditions.checkArgument(Preconditions.java:119)
[info]   at com.google.uzaygezen.core.ranges.LongRangeHome.toRange(LongRangeHome.java:40)
[info]   at com.google.uzaygezen.core.ranges.LongRangeHome.toRange(LongRangeHome.java:27)
[info]   at com.google.uzaygezen.core.ranges.RangeUtil.toOrthotope(RangeUtil.java:50)
[info]   at com.google.uzaygezen.core.SimpleRegionInspector.assess(SimpleRegionInspector.java:127)
[info]   at com.google.uzaygezen.core.BacktrackingQueryBuilder.visit(BacktrackingQueryBuilder.java:121)
[info]   at com.google.uzaygezen.core.ZoomingSpaceVisitorAdapter.visit(ZoomingSpaceVisitorAdapter.java:66)
[info]   at com.google.uzaygezen.core.CompactHilbertCurve.accept(CompactHilbertCurve.java:182)
[info]   at geotrellis.spark.io.index.hilbert.HilbertSpaceTimeKeyIndex.indexRanges(HilbertSpaceTimeKeyIndex.scala:113)
[info]   at geotrellis.spark.io.index.hilbert.HilbertSpaceTimeKeyIndexSpec$$anonfun$1$$anonfun$apply$mcV$sp$5.apply$mcV$sp(HilbertSpaceTimeKeyIndexSpec.scala:93)

hilbert-error-test.scala

import geotrellis.spark.io.index._
import geotrellis.spark.io.json._
import spray.json._

it("does not throw"){
  val k1 = SpaceTimeKey(0, 0, new DateTime(2000,1,1,0,0,0))
  val k2 = SpaceTimeKey(0, 0, new DateTime(2015,12,31,11,59,59))
  val kb = KeyBounds(k1, k2)
  val kim = HilbertKeyIndexMethod(12)
  val ki = kim.createIndex(kb)
  ki.indexRanges(kb)
}