Can somebody review the patch attached to ticket #10480?
http://dev.rubyonrails.org/ticket/10480
A has_many through association including the group option doesn't use the group when counting. Meaning person.grouped_relations.count will return a different value than person.grouped_relations.length. This first will construct a query without taking group into account and the latter will properly fetch all relations and return the length of the result set.
Thanks, Remco