diff --git a/src/grib_accessor_class_long_vector.c b/src/grib_accessor_class_long_vector.c
index 74bbb1a9e..3f995dc11 100644
--- a/src/grib_accessor_class_long_vector.c
+++ b/src/grib_accessor_class_long_vector.c
@@ -185,12 +185,12 @@ static int unpack_long(grib_accessor* a, long* val, size_t* len)
 
     /*TODO implement the dirty mechanism to avoid to unpack every time */
     err = grib_get_size(grib_handle_of_accessor(a), self->vector, &size);
-    DebugAssert(!err);
+    if (err) return err;
     DebugAssert(size > 0);
     vector = (long*)grib_context_malloc(a->context, sizeof(long) * size);
     err = grib_unpack_long(va, vector, &size);
-    DebugAssert(!err);
     grib_context_free(a->context, vector);
+    if (err) return err;
 
     *val = v->v[self->index];