diff --git a/app/models/poll/answer.rb b/app/models/poll/answer.rb
index ad1827e59..b99ffcef6 100644
--- a/app/models/poll/answer.rb
+++ b/app/models/poll/answer.rb
@@ -36,7 +36,7 @@ class Poll::Answer < ApplicationRecord
   private
 
     def max_votes
-      return if !question || !author || question&.unique? || persisted?
+      return if !question || !author || persisted?
 
       author.lock!
 
diff --git a/app/models/poll/question.rb b/app/models/poll/question.rb
index 813b7882e..729cdbe46 100644
--- a/app/models/poll/question.rb
+++ b/app/models/poll/question.rb
@@ -28,7 +28,7 @@ class Poll::Question < ApplicationRecord
   accepts_nested_attributes_for :question_options, reject_if: :all_blank, allow_destroy: true
   accepts_nested_attributes_for :votation_type
 
-  delegate :max_votes, :multiple?, :vote_type, to: :votation_type, allow_nil: true
+  delegate :multiple?, :vote_type, to: :votation_type, allow_nil: true
 
   scope :by_poll_id,    ->(poll_id) { where(poll_id: poll_id) }
 
@@ -90,6 +90,14 @@ class Poll::Question < ApplicationRecord
     votation_type.nil? || votation_type.unique?
   end
 
+  def max_votes
+    if multiple?
+      votation_type.max_votes
+    else
+      1
+    end
+  end
+
   def find_or_initialize_user_answer(user, title)
     answer = answers.find_or_initialize_by(find_by_attributes(user, title))
     answer.answer = title
diff --git a/spec/models/poll/answer_spec.rb b/spec/models/poll/answer_spec.rb
index dc3dee8f5..9c217851f 100644
--- a/spec/models/poll/answer_spec.rb
+++ b/spec/models/poll/answer_spec.rb
@@ -30,6 +30,17 @@ describe Poll::Answer do
       expect(answer).not_to be_valid
     end
 
+    it "is not valid if there's already an answer to that question" do
+      author = create(:user)
+      question = create(:poll_question, :yes_no)
+
+      create(:poll_answer, author: author, question: question)
+
+      answer = build(:poll_answer, author: author, question: question)
+
+      expect(answer).not_to be_valid
+    end
+
     it "is not valid when user already reached multiple answers question max votes" do
       author = create(:user)
       question = create(:poll_question_multiple, :abc, max_votes: 2)
@@ -40,20 +51,6 @@ describe Poll::Answer do
       expect(answer).not_to be_valid
     end
 
-    it "validates max votes when creating answers at the same time", :race_condition do
-      author = create(:user, :level_two)
-      question = create(:poll_question_multiple, :abc, max_votes: 2)
-      create(:poll_answer, question: question, answer: "Answer A", author: author)
-      answer = build(:poll_answer, question: question, answer: "Answer B", author: author)
-      other_answer = build(:poll_answer, question: question, answer: "Answer C", author: author)
-
-      [answer, other_answer].map do |a|
-        Thread.new { a.save }
-      end.each(&:join)
-
-      expect(Poll::Answer.count).to be 2
-    end
-
     it "is valid for answers included in the Poll::Question's question_options list" do
       question = create(:poll_question)
       create(:poll_question_option, title: "One", question: question)
@@ -66,6 +63,36 @@ describe Poll::Answer do
 
       expect(build(:poll_answer, question: question, answer: "Four")).not_to be_valid
     end
+
+    context "creating answers at the same time", :race_condition do
+      it "validates max votes on single-answer questions" do
+        author = create(:user)
+        question = create(:poll_question, :yes_no)
+
+        answer = build(:poll_answer, author: author, question: question, answer: "Yes")
+        other_answer = build(:poll_answer, author: author, question: question, answer: "No")
+
+        [answer, other_answer].map do |poll_answer|
+          Thread.new { poll_answer.save }
+        end.each(&:join)
+
+        expect(Poll::Answer.count).to be 1
+      end
+
+      it "validates max votes on multiple-answer questions" do
+        author = create(:user, :level_two)
+        question = create(:poll_question_multiple, :abc, max_votes: 2)
+        create(:poll_answer, question: question, answer: "Answer A", author: author)
+        answer = build(:poll_answer, question: question, answer: "Answer B", author: author)
+        other_answer = build(:poll_answer, question: question, answer: "Answer C", author: author)
+
+        [answer, other_answer].map do |poll_answer|
+          Thread.new { poll_answer.save }
+        end.each(&:join)
+
+        expect(Poll::Answer.count).to be 2
+      end
+    end
   end
 
   describe "#save_and_record_voter_participation" do
@@ -92,14 +119,14 @@ describe Poll::Answer do
 
       expect(poll.reload.voters.size).to eq(1)
 
-      answer = create(:poll_answer, question: question, author: author, answer: "No")
-      answer.save_and_record_voter_participation
+      updated_answer = answer.question.find_or_initialize_user_answer(answer.author, "No")
+      updated_answer.save_and_record_voter_participation
 
       expect(poll.reload.voters.size).to eq(1)
 
       voter = poll.voters.first
-      expect(voter.document_number).to eq(answer.author.document_number)
-      expect(voter.poll_id).to eq(answer.poll.id)
+      expect(voter.document_number).to eq(updated_answer.author.document_number)
+      expect(voter.poll_id).to eq(updated_answer.poll.id)
     end
 
     it "does not save the answer if the voter is invalid" do
@@ -112,6 +139,22 @@ describe Poll::Answer do
 
       expect(answer).not_to be_persisted
     end
+
+    it "does not create two voters when creating two answers at the same time", :race_condition do
+      answer = build(:poll_answer, question: question, author: author, answer: "Yes")
+      other_answer = build(:poll_answer, question: question, author: author, answer: "No")
+
+      [answer, other_answer].map do |poll_answer|
+        Thread.new do
+          begin
+            poll_answer.save_and_record_voter_participation
+          rescue ActiveRecord::RecordInvalid
+          end
+        end
+      end.each(&:join)
+
+      expect(Poll::Voter.count).to be 1
+    end
   end
 
   describe "#destroy_and_remove_voter_participation" do