diff --git a/lark/parse_tree_builder.py b/lark/parse_tree_builder.py
index a6e28e5..595ef8c 100644
--- a/lark/parse_tree_builder.py
+++ b/lark/parse_tree_builder.py
@@ -27,7 +27,7 @@ class PropagatePositions:
     def __call__(self, children):
         res = self.node_builder(children)
 
-        if isinstance(res, Tree):
+        if isinstance(res, Tree) and getattr(res.meta, 'empty', True):
             res.meta.empty = True
 
             for c in children: