Remove callback as we already update accordingly on services

app/models/merge_request.rb

@@ -56,7 +56,6 @@ class MergeRequest < ActiveRecord::Base
   after_create :ensure_merge_request_diff, unless: :importing?
   after_update :clear_memoized_shas
   after_update :reload_diff_if_branch_changed
-  after_update :mark_as_unchecked_if_target_branch_changed
 
   # When this attribute is true some MR validation is ignored
   # It allows us to close or modify broken merge requests
@@ -562,12 +561,6 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  def mark_as_unchecked_if_target_branch_changed
-    return unless target_branch_changed?
-
-    mark_as_unchecked
-  end
-
   def reload_diff(current_user = nil)
     return unless open?
 

spec/models/merge_request_spec.rb

@@ -77,23 +77,6 @@ describe MergeRequest do
         expect(MergeRequest::Metrics.count).to eq(1)
       end
     end
-
-    describe '#mark_as_unchecked_if_target_branch_changed' do
-      let(:merge_request) { create(:merge_request, merge_status: :can_be_merged) }
-
-      it 'marks MR as unchecked if target_branch changes' do
-        expect { merge_request.update!(target_branch: 'bar') }
-          .to change(merge_request, :merge_status)
-          .from('can_be_merged')
-          .to('unchecked')
-      end
-
-      it 'does not marks MR as unchecked when target_branch does not changes' do
-        expect { merge_request.update!(title: 'foo') }
-          .not_to change(merge_request, :merge_status)
-          .from('can_be_merged')
-      end
-    end
   end
 
   describe 'respond to' do