Revert unrelated change

Author: phofl

pandas/core/internals/managers.py

@@ -384,8 +384,10 @@ def setitem(self: T, indexer, value) -> T:
         return self.apply("setitem", indexer=indexer, value=value)
 
     def putmask(self, mask, new, align: bool = True):
-        if using_copy_on_write() and any(
-            not self._has_no_reference_block(i) for i in range(len(self.blocks))
+        if (
+            using_copy_on_write()
+            and self.refs is not None
+            and not all(ref is None for ref in self.refs)
         ):
             # some reference -> copy full dataframe
             # TODO(CoW) this could be optimized to only copy the blocks that would