diff --git a/Changelog.md b/Changelog.md
index 4d7839848..b411f0bd5 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -40,6 +40,7 @@
 * Fix error with invite link box shows on search results page even if invites have been turned off. [#3708](https://github.com/diaspora/diaspora/pull/3708)
 * Fix misconfiguration of Devise to allow the session to be remembered. [#3472](https://github.com/diaspora/diaspora/issues/3472)
 * Fix problem with show reshares_count in stream. [#3700](https://github.com/diaspora/diaspora/pull/3700)
+* Fix error with notifications count in mobile. [#3721](https://github.com/diaspora/diaspora/pull/3721)
 
 ## Gem updates
 
diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index 886ccc4bd..d6435b1c4 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -105,7 +105,7 @@ class PostsController < ApplicationController
   end
 
   def mark_corresponding_notification_read
-    if notification = Notification.where(:recipient_id => current_user.id, :target_id => @post.id).first
+    if notification = Notification.where(:recipient_id => current_user.id, :target_id => @post.id, :unread => true).first
       notification.unread = false
       notification.save
     end
diff --git a/spec/controllers/posts_controller_spec.rb b/spec/controllers/posts_controller_spec.rb
index 62b216956..de647d540 100644
--- a/spec/controllers/posts_controller_spec.rb
+++ b/spec/controllers/posts_controller_spec.rb
@@ -41,12 +41,14 @@ describe PostsController do
       end
 
       it 'marks a corresponding notification as read' do
-        note = Notification.create(:recipient => alice, :target => @message, :unread => true)
+        # Ensure that it doesn't mark a read notification as read
+        FactoryGirl.create(:notification, :recipient => alice, :target => @message, :unread => false)
+        note = FactoryGirl.create(:notification, :recipient => alice, :target => @message, :unread => true)
 
-        lambda{
+        expect {
           get :show, :id => @message.id
           note.reload
-        }.should change(note, :unread).from(true).to(false)
+        }.to change(note, :unread).from(true).to(false)
       end
 
       it 'succeeds with a AS/photo' do