diff --git a/dspace-api/src/main/java/org/dspace/content/Collection.java b/dspace-api/src/main/java/org/dspace/content/Collection.java
index d94f48c9ad..1d4c9bbefe 100644
--- a/dspace-api/src/main/java/org/dspace/content/Collection.java
+++ b/dspace-api/src/main/java/org/dspace/content/Collection.java
@@ -88,8 +88,7 @@ public class Collection extends DSpaceObject implements DSpaceObjectLegacySuppor
             joinColumns = {@JoinColumn(name = "collection_id") },
             inverseJoinColumns = {@JoinColumn(name = "community_id") }
     )
-    @Sort(type = SortType.COMPARATOR, comparator = NameAscendingComparator.class)
-    private Set<Community> communities = new TreeSet<>(new NameAscendingComparator());
+    private Set<Community> communities = new HashSet<>();
 
     @Transient
     private transient CollectionService collectionService;
@@ -270,7 +269,10 @@ public class Collection extends DSpaceObject implements DSpaceObjectLegacySuppor
     public List<Community> getCommunities() throws SQLException
     {
         // We return a copy because we do not want people to add elements to this collection directly.
-        return Arrays.asList(communities.toArray(new Community[]{}));
+        // We return a list to maintain backwards compatibility
+        Community[] output = communities.toArray(new Community[]{});
+        Arrays.sort(output, new NameAscendingComparator());
+        return Arrays.asList(output);
     }
 
     void addCommunity(Community community) {
@@ -278,7 +280,7 @@ public class Collection extends DSpaceObject implements DSpaceObjectLegacySuppor
         setModified();
     }
 
-    void removeCommunity(Community community){
+    void removeCommunity(Community community) {
         this.communities.remove(community);
         setModified();
     }
diff --git a/dspace-api/src/main/java/org/dspace/content/Community.java b/dspace-api/src/main/java/org/dspace/content/Community.java
index 496df5fb4a..e18356af41 100644
--- a/dspace-api/src/main/java/org/dspace/content/Community.java
+++ b/dspace-api/src/main/java/org/dspace/content/Community.java
@@ -50,16 +50,13 @@ public class Community extends DSpaceObject implements DSpaceObjectLegacySupport
             joinColumns = {@JoinColumn(name = "parent_comm_id") },
             inverseJoinColumns = {@JoinColumn(name = "child_comm_id") }
     )
-    @Sort(type = SortType.COMPARATOR, comparator = NameAscendingComparator.class)
-    private Set<Community> subCommunities = new TreeSet<Community>(new NameAscendingComparator());
+    private Set<Community> subCommunities = new HashSet<>();
 
     @ManyToMany(fetch = FetchType.LAZY, mappedBy = "subCommunities")
-    @Sort(type = SortType.COMPARATOR, comparator = NameAscendingComparator.class)
-    private Set<Community> parentCommunities = new TreeSet<Community>(new NameAscendingComparator());;
+    private Set<Community> parentCommunities = new HashSet<>();
 
     @ManyToMany(fetch = FetchType.LAZY, mappedBy = "communities", cascade = {CascadeType.PERSIST})
-    @Sort(type = SortType.COMPARATOR, comparator = NameAscendingComparator.class)
-    private Set<Collection> collections =new TreeSet<Collection>(new NameAscendingComparator());;
+    private Set<Collection> collections = new HashSet<>();
 
     @OneToOne
     @JoinColumn(name = "admin")
@@ -150,7 +147,10 @@ public class Community extends DSpaceObject implements DSpaceObjectLegacySupport
     public List<Collection> getCollections()
     {
         // We return a copy because we do not want people to add elements to this collection directly.
-        return Arrays.asList(collections.toArray(new Collection[]{}));
+        // We return a list to maintain backwards compatibility
+        Collection[] output = collections.toArray(new Collection[]{});
+        Arrays.sort(output, new NameAscendingComparator());
+        return Arrays.asList(output);
     }
 
     void addCollection(Collection collection)
@@ -173,7 +173,10 @@ public class Community extends DSpaceObject implements DSpaceObjectLegacySupport
     public List<Community> getSubcommunities()
     {
         // We return a copy because we do not want people to add elements to this collection directly.
-        return Arrays.asList(subCommunities.toArray(new Community[]{}));
+        // We return a list to maintain backwards compatibility
+        Community[] output = subCommunities.toArray(new Community[]{});
+        Arrays.sort(output, new NameAscendingComparator());
+        return Arrays.asList(output);
     }
 
     /**
@@ -185,7 +188,10 @@ public class Community extends DSpaceObject implements DSpaceObjectLegacySupport
     public List<Community> getParentCommunities()
     {
         // We return a copy because we do not want people to add elements to this collection directly.
-        return Arrays.asList(parentCommunities.toArray(new Community[]{}));
+        // We return a list to maintain backwards compatibility
+        Community[] output = parentCommunities.toArray(new Community[]{});
+        Arrays.sort(output, new NameAscendingComparator());
+        return Arrays.asList(output);
     }
 
     void addParentCommunity(Community parentCommunity) {
@@ -193,13 +199,13 @@ public class Community extends DSpaceObject implements DSpaceObjectLegacySupport
     }
 
     void clearParentCommunities(){
-        this.parentCommunities.clear();
-        this.parentCommunities = null;
+        parentCommunities.clear();
     }
 
     public void removeParentCommunity(Community parentCommunity)
     {
-        this.parentCommunities.remove(parentCommunity);
+        parentCommunities.remove(parentCommunity);
+        setModified();
     }
 
     /**
diff --git a/dspace-api/src/main/java/org/dspace/content/Item.java b/dspace-api/src/main/java/org/dspace/content/Item.java
index aca2738d54..49ab4b8caa 100644
--- a/dspace-api/src/main/java/org/dspace/content/Item.java
+++ b/dspace-api/src/main/java/org/dspace/content/Item.java
@@ -79,8 +79,7 @@ public class Item extends DSpaceObject implements DSpaceObjectLegacySupport
             joinColumns = {@JoinColumn(name = "item_id") },
             inverseJoinColumns = {@JoinColumn(name = "collection_id") }
     )
-    @Sort(type = SortType.COMPARATOR, comparator = NameAscendingComparator.class)
-    private final Set<Collection> collections = new TreeSet<>(new NameAscendingComparator());
+    private final Set<Collection> collections = new HashSet<>();
 
     @ManyToMany(fetch = FetchType.LAZY, mappedBy = "items")
     private final List<Bundle> bundles = new ArrayList<>();
@@ -233,7 +232,10 @@ public class Item extends DSpaceObject implements DSpaceObjectLegacySupport
     public List<Collection> getCollections()
     {
         // We return a copy because we do not want people to add elements to this collection directly.
-        return Arrays.asList(collections.toArray(new Collection[]{}));
+        // We return a list to maintain backwards compatibility
+        Collection[] output = collections.toArray(new Collection[]{});
+        Arrays.sort(output, new NameAscendingComparator());
+        return Arrays.asList(output);
     }
 
     void addCollection(Collection collection)