wayland-server sends error on calling a method not supported by bound protocol version on sys, but not rs backend

[ids1024]

libwayland has this code to generate an error:

if (!(resource_flags & WL_MAP_ENTRY_LEGACY) &&
    resource->version > 0 && resource->version < since) {
	wl_resource_post_error(client->display_resource,
			       WL_DISPLAY_ERROR_INVALID_METHOD,
			       "invalid method %d (since %d < %d)"
			       ", object %s#%u",
			       opcode, resource->version, since,
			       object->interface->name,
			       object->id);
	break;
}

But without server_system, nothing similar seems to be sent by the rs backend.