diff --git a/src/behavior3 b/src/behavior3
index 16334ea..37eea09 160000
--- a/src/behavior3
+++ b/src/behavior3
@@ -1 +1 @@
-Subproject commit 16334eab4c36a2a8b2445e9fa11e44673f0d7252
+Subproject commit 37eea095997f35eaf96fafc440207270a2c94f0d
diff --git a/src/misc/b3util.ts b/src/misc/b3util.ts
index 2b0942a..c308fe6 100644
--- a/src/misc/b3util.ts
+++ b/src/misc/b3util.ts
@@ -502,13 +502,14 @@ const checkNodeData = (data: NodeData | null | undefined, printer: ErrorPrinter)
   }
   if (conf.args) {
     const args: { [k: string]: unknown } = {};
+    data.args ||= {};
     for (let i = 0; i < conf.args.length; i++) {
       const key = conf.args[i].name;
-      if (data.args && data.args[key] === undefined && conf.args[i].default !== undefined) {
+      if (data.args[key] === undefined && conf.args[i].default !== undefined) {
         data.args[key] = conf.args[i].default;
       }
 
-      const value = data.args?.[key];
+      const value = data.args[key];
       if (value !== undefined) {
         args[key] = value;
       }