diff --git a/src/nub.ts b/src/nub.ts
index 21463a8c472f252637c6d665058a50a8846fbbb9..fb195466e4a9c83c4d06913f0efd7650e232e1e6 100644
--- a/src/nub.ts
+++ b/src/nub.ts
@@ -150,7 +150,10 @@ export abstract class Nub extends ComputeNode implements IObservable {
      */
     public unsetCalculatedParam(except: ParamDefinition) {
         for (const p of this.parameterIterator) {
-            if (p !== except) {
+            if (
+                p.valueMode === ParamValueMode.CALCUL
+                && p !== except
+            ) {
                 p.setValueMode(ParamValueMode.SINGLE, false);
             }
         }