diff --git a/src/rougail/object_model.py b/src/rougail/object_model.py
index 7f2c51245..e2d7fdc5c 100644
--- a/src/rougail/object_model.py
+++ b/src/rougail/object_model.py
@@ -589,7 +589,9 @@ class VariablePropertyCalculation(_VariableCalculation):
             identifier,
             needs_multi=False,
         )
-        if params[None] and "variable" in params[None][0]:
+        if objectspace.force_optional and (not params[None] or "variable" not in params[None][0]):
+            params = {None: [None, None, False]}
+        else:
             variable = params[None][0]["variable"]
             if self.when is not undefined:
                 if self.version == "1.0":