diff --git a/addons/web_kanban/static/src/js/kanban_view.js b/addons/web_kanban/static/src/js/kanban_view.js
index 15e0512bcef..b2f3f55c10a 100644
--- a/addons/web_kanban/static/src/js/kanban_view.js
+++ b/addons/web_kanban/static/src/js/kanban_view.js
@@ -215,7 +215,7 @@ var KanbanView = View.extend({
             } else {
                 _.each(groups, function (group) {
                     var value = group.attributes.value;
-                    group.id = value;
+                    group.id = value instanceof Array ? value[0] : value;
                     var field = self.fields_view.fields[self.group_by_field];
                     if (field && field.type === "selection") {
                         value= _.find(field.selection, function (s) { return s[0] === group.attributes.value; });