diff --git a/pyaerocom/ungriddeddata.py b/pyaerocom/ungriddeddata.py
index 834ab0bd7..7c32ad8c8 100644
--- a/pyaerocom/ungriddeddata.py
+++ b/pyaerocom/ungriddeddata.py
@@ -2048,6 +2048,7 @@ def _new_from_meta_blocks(self, meta_indices, totnum_new):
                 stop = data_idx_new + totnum
 
                 new._data[data_idx_new:stop, :] = self._data[indices, :]
+                new._data[data_idx_new:stop, new._METADATAKEYINDEX] = meta_idx_new
                 new.meta_idx[meta_idx_new][var] = np.arange(data_idx_new, stop)
                 new.var_idx[var] = self.var_idx[var]
                 data_idx_new += totnum