diff --git a/app/models/page_groupers/group_allyship.rb b/app/models/page_groupers/group_allyship.rb
index a63382e1c..4e3e00c84 100644
--- a/app/models/page_groupers/group_allyship.rb
+++ b/app/models/page_groupers/group_allyship.rb
@@ -15,6 +15,6 @@ class GroupAllyship < ApplicationRecord
     this_object  = Group.find_by(id: self.group_id)
     other_object = Group.find_by(id: self.ally_id)
 
-    other_object.allies.delete this_object
+    other_object.allies.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/group_enemyship.rb b/app/models/page_groupers/group_enemyship.rb
index d3f2972ef..d0cb01d43 100644
--- a/app/models/page_groupers/group_enemyship.rb
+++ b/app/models/page_groupers/group_enemyship.rb
@@ -15,6 +15,6 @@ class GroupEnemyship < ApplicationRecord
     this_object  = Group.find_by(id: self.group_id)
     other_object = Group.find_by(id: self.enemy_id)
 
-    other_object.enemies.delete this_object
+    other_object.enemies.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/sistergroupship.rb b/app/models/page_groupers/sistergroupship.rb
index 464e38256..01a7543f0 100644
--- a/app/models/page_groupers/sistergroupship.rb
+++ b/app/models/page_groupers/sistergroupship.rb
@@ -15,6 +15,6 @@ class Sistergroupship < ApplicationRecord
     this_object  = Group.find_by(id: self.group_id)
     other_object = Group.find_by(id: self.sistergroup_id)
 
-    other_object.sistergroups.delete this_object
+    other_object.sistergroups.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/subgroupship.rb b/app/models/page_groupers/subgroupship.rb
index 22bb06c7f..e1aa651e4 100644
--- a/app/models/page_groupers/subgroupship.rb
+++ b/app/models/page_groupers/subgroupship.rb
@@ -18,6 +18,6 @@ class Subgroupship < ApplicationRecord
     this_object  = Group.find_by(id: self.group_id)
     other_object = Group.find_by(id: self.subgroup_id)
 
-    other_object.supergroups.delete(this_object)
+    other_object.supergroups.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/technology_child_technology.rb b/app/models/page_groupers/technology_child_technology.rb
index 3816ef0d6..decf5dc6d 100644
--- a/app/models/page_groupers/technology_child_technology.rb
+++ b/app/models/page_groupers/technology_child_technology.rb
@@ -20,6 +20,6 @@ class TechnologyChildTechnology < ApplicationRecord
     this_object  = Technology.find_by(id: self.technology_id)
     other_object = Technology.find_by(id: self.child_technology_id)
 
-    other_object.parent_technologies.delete(this_object)
+    other_object.parent_technologies.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/technology_parent_technology.rb b/app/models/page_groupers/technology_parent_technology.rb
index ec51bb467..1147ed6f4 100644
--- a/app/models/page_groupers/technology_parent_technology.rb
+++ b/app/models/page_groupers/technology_parent_technology.rb
@@ -20,6 +20,6 @@ class TechnologyParentTechnology < ApplicationRecord
     this_object  = Technology.find_by(id: self.technology_id)
     other_object = Technology.find_by(id: self.parent_technology_id)
 
-    other_object.child_technologies.delete(this_object)
+    other_object.child_technologies.delete(this_object) if other_object.present?
   end
 end
diff --git a/app/models/page_groupers/technology_related_technology.rb b/app/models/page_groupers/technology_related_technology.rb
index e8c187721..5a4f73ee7 100644
--- a/app/models/page_groupers/technology_related_technology.rb
+++ b/app/models/page_groupers/technology_related_technology.rb
@@ -14,6 +14,6 @@ class TechnologyRelatedTechnology < ApplicationRecord
     this_object  = Technology.find_by(id: self.technology_id)
     other_object = Technology.find_by(id: self.related_technology_id)
 
-    other_object.related_technologies.delete(this_object)
+    other_object.related_technologies.delete(this_object) if other_object.present?
   end
 end