Scoped Uniquess Validation throwing an error erroneously.

Problem Description

Problem:

So here, if I go into the console and run SuggestionVote.count I get 3 votes total by 2 other user ID's which are 2 and 3.

I log in as user ID 1, which has no suggestion votes. I click on the vote link and I get an error flashed:
Problem: ["User You can only vote once for a suggestion."]

I go back into the Rails console and do SuggestionVote.count and it now it shows 4.

So I'm getting the error message but it is creating the entry, but only the first time. If I manually go to the vote link again and recheck the Rails console I'm still at 4 votes - it is indeed not allowing multiple votes. Why it gives me the error but still creates the vote is a mystery.

Additionally the specs all pass successfully. So underlying the code works as it should. Could this be related to Turbolinks in some way?

suggestion_vote.rb

class SuggestionVote < ActiveRecord::Base
  belongs_to :user
  belongs_to :suggestion
  
  validates :user_id, uniqueness: { scope: :suggestion_id, message: "You can only vote once for a suggestion." }
end

suggestion_vote_controller.rb

class SuggestionVotesController < ApplicationController
  before_action :authenticate_user!
  before_action :set_suggestion
  
  def vote
     @suggestion_vote = SuggestionVote.new(suggestion: @suggestion, user: current_user)
     respond_to do |format|
      if @suggestion_vote.save
        format.html { redirect_to suggestions_path, notice: "Voted for #{@suggestion.title}" }
        format.json { render action: 'show', status: :created, location: suggestions_path }
      else
        format.html { redirect_to suggestions_path, alert: "Problem: #{@suggestion_vote.errors.full_messages}" }
        format.json { render json: @suggestion_vote.errors.full_messages, status: :unprocessable_entity }
      end
    end
  end

  def unvote
    @suggestion_votes = SuggestionVote.where('suggestion_id = ? and user_id = ?', @suggestion.id, current_user.id)
    @suggestion_votes.first.destroy
    respond_to do |format|
      format.html { redirect_to suggestions_path }
      format.json { head :no_content }
    end
  end
  
  private
    def set_suggestion
      @suggestion = Suggestion.find(params[:id])
    end

end

suggestion_vote_controller_spec.rb

require 'spec_helper'

describe SuggestionVotesController do
  login_user
  before(:each) { @suggestion = FactoryGirl.create(:suggestion, creator: @user) }
  
  describe "GET 'vote'" do
    #before(:each) { @suggestion = FactoryGirl.create(:suggestion, creator: @user) }
    
    describe "when not voted for already" do
      it "redirects to all suggestions" do
        get :vote, {id: @suggestion.to_param}
        response.should redirect_to suggestions_path
      end
      
      it "adds a new vote" do
        expect {
          get :vote, {id: @suggestion.to_param}
        }.to change(SuggestionVote, :count).by(1)
      end
      
      it "adds a flash notice notifying the user about their vote" do
        get :vote, {id: @suggestion.to_param}        
        flash[:notice].should =~ /Voted for/i
      end
    end
    
    describe "when already voted for" do
      before(:each) { FactoryGirl.create(:suggestion_vote, suggestion: @suggestion, user: @user) }
      
      it "redirects to all suggestions" do
        get :vote, {id: @suggestion.to_param}
        response.should redirect_to suggestions_path
      end
      
      it "adds a flash notice notifying the user about their vote" do
        get :vote, {id: @suggestion.to_param}        
        flash[:alert].should =~ /Problem: /i
      end
    end
  end 

  describe "GET 'unvote'" do
    before(:each) { FactoryGirl.create(:suggestion_vote, suggestion: @suggestion, user: @user) }
    
    it "redirects to all suggestions" do
      delete :unvote, {id: @suggestion.id}
      response.should redirect_to suggestions_path
    end
    it "adds a new vote" do
      expect {
        delete :unvote, {id: @suggestion.id}
      }.to change(SuggestionVote, :count).by(-1)
    end
  end

end