diff --git a/src/script/common/c_converter.cpp b/src/script/common/c_converter.cpp
index 446f88f3d..f0511d586 100644
--- a/src/script/common/c_converter.cpp
+++ b/src/script/common/c_converter.cpp
@@ -58,6 +58,7 @@ extern "C" {
  */
 static void read_v3_aux(lua_State *L, int index)
 {
+	CHECK_POS_TAB(index);
 	lua_pushvalue(L, index);
 	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_READ_VECTOR);
 	lua_insert(L, -2);