diff --git a/hosts/ocaml/lib/sx_vm.ml b/hosts/ocaml/lib/sx_vm.ml
index 4bc830e..d6a99a4 100644
--- a/hosts/ocaml/lib/sx_vm.ml
+++ b/hosts/ocaml/lib/sx_vm.ml
@@ -233,9 +233,13 @@ let rec run vm =
       let name = match consts.(idx) with String s -> s | _ -> "" in
       let args = List.init argc (fun _ -> pop vm) |> List.rev in
       let result =
-        (match Sx_primitives.get_primitive name with
-         | NativeFn (_, fn) -> fn args
-         | _ -> Nil)
+        try
+          (match Sx_primitives.get_primitive name with
+           | NativeFn (_, fn) -> fn args
+           | _ -> Nil)
+        with Eval_error msg ->
+          raise (Eval_error (Printf.sprintf "%s (in CALL_PRIM \"%s\" with %d args)"
+            msg name argc))
       in
       push vm result;
       run vm
@@ -316,14 +320,15 @@ and code_from_value v =
     { arity; locals = arity + 16; bytecode = bc_list; constants }
   | _ -> { arity = 0; locals = 16; bytecode = [||]; constants = [||] }
 
-(** Execute a closure with arguments — creates a new VM frame.
-    The closure carries its upvalue cells for captured variables. *)
+(** Execute a closure with arguments.
+    If called from within a VM (via NativeFn wrapper from for-each/map),
+    the upvalue cells already contain the captured values — no parent
+    frame needed. The fresh VM is fine because upvalues are heap-allocated
+    cells, not stack references. *)
 and call_closure cl args globals =
   let vm = create globals in
   let frame = { closure = cl; ip = 0; base = vm.sp; local_cells = Hashtbl.create 4 } in
-  (* Push args as locals *)
   List.iter (fun a -> push vm a) args;
-  (* Pad remaining locals with nil *)
   for _ = List.length args to cl.code.locals - 1 do push vm Nil done;
   vm.frames <- [frame];
   run vm;
diff --git a/shared/sx/ocaml_bridge.py b/shared/sx/ocaml_bridge.py
index 4e6c277..517ed11 100644
--- a/shared/sx/ocaml_bridge.py
+++ b/shared/sx/ocaml_bridge.py
@@ -333,13 +333,16 @@ class OcamlBridge:
             _logger.info("Loaded %d definitions from .sx files into OCaml kernel (%d skipped)",
                          count, skipped)
 
-            # Compile adapter-sx.sx to bytecode and load as VM module.
-            # All aser functions become NativeFn VM closures in the
-            # kernel env. The CEK calls them as NativeFn → VM executes.
-            try:
-                await self._compile_adapter_module()
-            except Exception as e:
-                _logger.warning("VM adapter compilation skipped: %s", e)
+            # VM adapter compilation: compile adapter-sx.sx to bytecode,
+            # load as VM module so aser runs compiled.
+            # DISABLED: vm-load-module replaces env bindings with NativeFn
+            # wrappers that break when the CEK machine calls other env
+            # functions during page eval. Need to isolate VM execution
+            # from CEK env to avoid cross-contamination.
+            # try:
+            #     await self._compile_adapter_module()
+            # except Exception as e:
+            #     _logger.warning("VM adapter compilation skipped: %s", e)
         except Exception as e:
             _logger.error("Failed to load .sx files into OCaml kernel: %s", e)
             self._components_loaded = False  # retry next time