diff --git a/binding-sandbox/binding-util.cpp b/binding-sandbox/binding-util.cpp
index d13ae71f..9900700e 100644
--- a/binding-sandbox/binding-util.cpp
+++ b/binding-sandbox/binding-util.cpp
@@ -33,7 +33,6 @@ void mkxp_sandbox::set_private_data(VALUE obj, void *ptr) {
     // Free the old value if it already exists (initialize called twice?)
     if (*(wasm_ptr_t *)(**sb() + data) != 0 && *(void **)(**sb() + *(wasm_ptr_t *)(**sb() + data)) != ptr) {
         sb()->rtypeddata_dfree(obj, *(wasm_ptr_t *)(**sb() + data));
-        sb()->sandbox_free(*(wasm_ptr_t *)(**sb() + data));
         *(wasm_ptr_t *)(**sb() + data) = 0;
     }
 
diff --git a/binding-sandbox/binding-util.h b/binding-sandbox/binding-util.h
index 6546a9df..5ce6d830 100644
--- a/binding-sandbox/binding-util.h
+++ b/binding-sandbox/binding-util.h
@@ -59,6 +59,7 @@
 #define SANDBOX_DEF_DFREE(T) \
     static void dfree(wasm_ptr_t _buf) { \
         delete *(T **)(**mkxp_sandbox::sb() + _buf); \
+        mkxp_sandbox::sb()->sandbox_free(_buf); \
     }
 
 #define SANDBOX_DEF_LOAD(T) \