diff --git a/src/main/jastadd/Backend.jadd b/src/main/jastadd/Backend.jadd
index b285919da1c5cdb9a04de7ec16863e06c330c861..bfff3b33d8e460348aa2739a55863f2276447f18 100644
--- a/src/main/jastadd/Backend.jadd
+++ b/src/main/jastadd/Backend.jadd
@@ -200,14 +200,18 @@ aspect BackendDirectedAPI {
     // resolve the entire list
     if (resolverHelper) {
       sb.append(ind(2) + "if (l != null) {\n");
+        sb.append(ind(3) + "boolean changed = false;\n");
         sb.append(ind(3) + "for (int i = 0; i < l.size(); i++) {\n");
           sb.append(ind(4) + ofTypeDecl() + " element = l.get(i);\n");
           sb.append(ind(4) + "if (element.unresolved()) {\n");
+            sb.append(ind(5) + "changed = true;\n");
             sb.append(ind(5) + ofTypeDecl() + " resolvedElement = resolve" + nameCapitalized() + "ByToken(element.asUnresolved().get__token(), i);\n");
             sb.append(ind(5) + "l.set(i, resolvedElement);\n");
           sb.append(ind(4) + "}\n");
         sb.append(ind(3) + "}\n");
-        sb.append(ind(3) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "if (changed) {\n");
+          sb.append(ind(4) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "}\n");
       sb.append(ind(2) + "}\n");
     }
     sb.append(ind(2) + "return l != null ? Collections.unmodifiableList(l) : Collections.emptyList();\n");
@@ -368,9 +372,11 @@ aspect BackendBidirectionalAPI {
     // resolve the entire list
     if (resolverHelper) {
       sb.append(ind(2) + "if (l != null) {\n");
+        sb.append(ind(3) + "boolean changed = false;\n");
         sb.append(ind(3) + "for (int i = 0; i < l.size(); i++) {\n");
           sb.append(ind(4) + ofTypeDecl() + " element = l.get(i);\n");
           sb.append(ind(4) + "if (element.unresolved()) {\n");
+            sb.append(ind(5) + "changed = true;\n");
             sb.append(ind(5) + ofTypeDecl() + " resolvedElement = resolve" + nameCapitalized() + "ByToken(element.asUnresolved().get__token(), i);\n");
             sb.append(ind(5) + "if (resolvedElement != null) {\n");
               sb.append(ind(6) + ASTNode.listClass + "<" + toTypeDecl() + "> otherList = resolvedElement.get" + getImplAttributeName() + "();\n");
@@ -383,7 +389,9 @@ aspect BackendBidirectionalAPI {
             sb.append(ind(5) + "l.set(i, resolvedElement);\n");
           sb.append(ind(4) + "}\n");
         sb.append(ind(3) + "}\n");
-        sb.append(ind(3) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "if (changed) {\n");
+          sb.append(ind(4) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "}\n");
       sb.append(ind(2) + "}\n");
     }
     sb.append(ind(2) + "return l != null ? Collections.unmodifiableList(l) : Collections.emptyList();\n");
@@ -439,9 +447,11 @@ aspect BackendBidirectionalAPI {
     // resolve the entire list
     if (resolverHelper) {
       sb.append(ind(2) + "if (l != null) {\n");
+        sb.append(ind(3) + "boolean changed = false;\n");
         sb.append(ind(3) + "for (int i = 0; i < l.size(); i++) {\n");
           sb.append(ind(4) + ofTypeDecl() + " element = l.get(i);\n");
           sb.append(ind(4) + "if (element.unresolved()) {\n");
+            sb.append(ind(5) + "changed = true;\n");
             sb.append(ind(5) + ofTypeDecl() + " resolvedElement = resolve" + nameCapitalized() + "ByToken(element.asUnresolved().get__token(), i);\n");
             sb.append(ind(5) + toTypeDecl() + " oldTarget = resolvedElement.get" + getImplAttributeName() + "();\n");
             sb.append(ind(5) + "if (oldTarget != null && oldTarget != this) {\n");
@@ -456,7 +466,9 @@ aspect BackendBidirectionalAPI {
             sb.append(ind(5) + "}\n");
           sb.append(ind(4) + "}\n");
         sb.append(ind(3) + "}\n");
-        sb.append(ind(3) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "if (changed) {\n");
+          sb.append(ind(4) + "set" + getImplAttributeName() + "(l);\n");
+        sb.append(ind(3) + "}\n");
       sb.append(ind(2) + "}\n");
     }
     sb.append(ind(2) + "return l != null ? Collections.unmodifiableList(l) : Collections.emptyList();\n");