diff --git a/docs/changelog.md b/docs/changelog.md
index 10aa6e59..2982581e 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -51,7 +51,8 @@ COMMIT;
 
 ## 1.0.0.rc-5
 
-- Fixed user autocompletion in permissions panel (cf #635)
+- fixed user autocompletion in permissions panel (cf #635)
+- fixed ternary choice dealing with unknown values (cf #633)
 
 ## 1.0.0.rc-4
 
diff --git a/umap/static/umap/js/umap.forms.js b/umap/static/umap/js/umap.forms.js
index 2c24f371..5bdd6ac2 100644
--- a/umap/static/umap/js/umap.forms.js
+++ b/umap/static/umap/js/umap.forms.js
@@ -538,7 +538,7 @@ L.FormBuilder.MultiChoice = L.FormBuilder.Element.extend({
 
     fetch: function () {
         var value = this.backup = this.toHTML();
-        if (value === null || value === undefined) value = this.default;
+        if (!this.container.querySelector('input[type="radio"][value="' + value + '"]')) value = this.default;
         this.container.querySelector('input[type="radio"][value="' + value + '"]').checked = true;
     },