diff --git a/app/models/observer/sla/ticket_rebuild_escalation.rb b/app/models/observer/sla/ticket_rebuild_escalation.rb
index 761dfd10e..6c27cc206 100644
--- a/app/models/observer/sla/ticket_rebuild_escalation.rb
+++ b/app/models/observer/sla/ticket_rebuild_escalation.rb
@@ -3,15 +3,7 @@
 class Observer::Sla::TicketRebuildEscalation < ActiveRecord::Observer
   observe 'sla', 'calendar'
 
-  def after_create(record)
-    _rebuild(record)
-  end
-
-  def after_update(record)
-    _check(record)
-  end
-
-  def after_delete(record)
+  def after_commit(record)
     _rebuild(record)
   end
 
diff --git a/app/models/observer/ticket/article_changes.rb b/app/models/observer/ticket/article_changes.rb
index c0184f6fa..337611fbf 100644
--- a/app/models/observer/ticket/article_changes.rb
+++ b/app/models/observer/ticket/article_changes.rb
@@ -27,7 +27,7 @@ class Observer::Ticket::ArticleChanges < ActiveRecord::Observer
       record.ticket.touch # rubocop:disable Rails/SkipsModelValidations
       return
     end
-    record.ticket.save
+    record.ticket.save!
   end
 
   def after_destroy(record)
diff --git a/app/models/observer/ticket/escalation_update.rb b/app/models/observer/ticket/escalation_update.rb
index c65a07b1a..085bce371 100644
--- a/app/models/observer/ticket/escalation_update.rb
+++ b/app/models/observer/ticket/escalation_update.rb
@@ -16,8 +16,6 @@ class Observer::Ticket::EscalationUpdate < ActiveRecord::Observer
 
     return true if record.destroyed?
 
-    return true if !record.saved_changes?
-
     record.escalation_calculation
   end
 end
diff --git a/app/models/observer/ticket/user_ticket_counter/background_job.rb b/app/models/observer/ticket/user_ticket_counter/background_job.rb
index a09904d06..de2ffadf1 100644
--- a/app/models/observer/ticket/user_ticket_counter/background_job.rb
+++ b/app/models/observer/ticket/user_ticket_counter/background_job.rb
@@ -26,6 +26,7 @@ class Observer::Ticket::UserTicketCounter::BackgroundJob
 
     # check if update is needed
     customer = User.lookup(id: @customer_id)
+    return true if !customer
     need_update = false
     if customer[:preferences][:tickets_open] != tickets_open
       need_update = true
@@ -36,7 +37,7 @@ class Observer::Ticket::UserTicketCounter::BackgroundJob
       customer[:preferences][:tickets_closed] = tickets_closed
     end
 
-    return if !need_update
+    return true if !need_update
     customer.updated_by_id = @updated_by_id
     customer.save
   end
diff --git a/test/unit/ticket_escalation_test.rb b/test/unit/ticket_escalation_test.rb
index c46bb97f5..1465f08db 100644
--- a/test/unit/ticket_escalation_test.rb
+++ b/test/unit/ticket_escalation_test.rb
@@ -115,27 +115,112 @@ class TicketEscalationTest < ActiveSupport::TestCase
     ticket.save!
     assert_not(ticket.has_changes_to_save?)
     assert(ticket.escalation_at)
-    assert_equal(ticket_escalation_at.to_s, ticket.escalation_at.to_s)
-
-    ticket.title = 'some value 123-1'
-    ticket.save!
-    assert_not(ticket.has_changes_to_save?)
-
-    assert(ticket.escalation_at)
-    assert_not_equal(ticket_escalation_at.to_s, ticket.escalation_at.to_s)
+    assert_equal((ticket_escalation_at - 30.minutes).to_s, ticket.escalation_at.to_s)
 
     sla.destroy!
     calendar.destroy!
 
-    ticket.save!
-    assert_not(ticket.has_changes_to_save?)
-    assert(ticket.escalation_at)
-
-    ticket.title = 'some value 123-2'
     ticket.save!
     assert_not(ticket.has_changes_to_save?)
     assert_not(ticket.escalation_at)
 
   end
 
+  test 'email process and reply via email' do
+
+    calendar = Calendar.create_or_update(
+      name: 'Escalation Test',
+      timezone: 'Europe/Berlin',
+      business_hours: {
+        mon: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        tue: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        wed: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        thu: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        fri: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        sat: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+        sun: {
+          active: true,
+          timeframes: [ ['00:00', '23:59'] ]
+        },
+      },
+      default: true,
+      ical_url: nil,
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+
+    sla = Sla.create_or_update(
+      name: 'test sla 1',
+      condition: {
+        'ticket.title' => {
+          operator: 'contains',
+          value: 'some value 123',
+        },
+      },
+      first_response_time: 60,
+      update_time: 180,
+      solution_time: 240,
+      calendar_id: calendar.id,
+      updated_by_id: 1,
+      created_by_id: 1,
+    )
+
+    email = "From: Bob Smith <customer@example.com>
+To: zammad@example.com
+Subject: some value 123
+
+Some Text"
+
+    ticket_p, article_p, user_p, mail = Channel::EmailParser.new.process({}, email)
+    ticket_p.reload
+    assert(ticket_p.escalation_at)
+    assert_equal(ticket_p.first_response_escalation_at.to_s, (ticket_p.created_at + 1.hour).to_s)
+    assert_equal(ticket_p.update_escalation_at.to_s, (ticket_p.created_at + 3.hours).to_s)
+    assert_equal(ticket_p.close_escalation_at.to_s, (ticket_p.created_at + 4.hours).to_s)
+    assert_equal(ticket_p.escalation_at.to_s, (ticket_p.created_at + 1.hour).to_s)
+
+    travel 3.hours
+    article = nil
+
+    ticket_p.with_lock do
+      article = Ticket::Article.create!(
+        ticket_id: ticket_p.id,
+        from: 'some_sender@example.com',
+        to: 'some_recipient@example.com',
+        subject: 'some subject',
+        message_id: 'some@id',
+        body: 'some message',
+        internal: false,
+        sender: Ticket::Article::Sender.where(name: 'Agent').first,
+        type: Ticket::Article::Type.where(name: 'email').first,
+        updated_by_id: 1,
+        created_by_id: 1,
+      )
+    end
+
+    ticket_p.reload
+    assert_equal(ticket_p.first_response_escalation_at.to_s, (ticket_p.created_at + 1.hour).to_s)
+    assert_equal(ticket_p.update_escalation_at.to_s, (ticket_p.last_contact_agent_at + 3.hours).to_s)
+    assert_equal(ticket_p.close_escalation_at.to_s, (ticket_p.created_at + 4.hours).to_s)
+    assert_equal(ticket_p.escalation_at.to_s, (ticket_p.created_at + 4.hours).to_s)
+
+  end
 end