Can't name has_one associated ':options'

[hulloitskai]

has_one :options doesn't seem to work—however, as a workaround, the following does work:

class MyThingSerializer < Oj::Serializer
  has_one :_options, as: :options, serializer: MyFancyOptionsSerializer do
    my_thing.options
  end
end

Any ideas behind the source of this strange behaviour?