ActiveRecord sum is broken on pages greater than 1

[donkey-hotei]

Hello, perhaps this is application specific but it seems as though summing on pages greater than one sums the records incorrectly. Although resolving the query to an array with map and then calling sum over the elements sums correctly.

[1] pry(main)> Trip.paginate(page: 2).sum('distance')
   (2.5ms)  SELECT  SUM("trips"."distance") FROM "trips" LIMIT $1 OFFSET $2  [["LIMIT", 30], ["OFFSET", 30]]
=> 0.0
[2] pry(main)> Trip.paginate(page: 1).sum('distance')
   (0.6ms)  SELECT  SUM("trips"."distance") FROM "trips" LIMIT $1 OFFSET $2  [["LIMIT", 30], ["OFFSET", 0]]
=> 10542.792252

Is this a bug in will_paginate ?