decorators: apply to propertiesdata mixin & one debug of previous

cf/decorators.py

@@ -3,7 +3,7 @@
 
 # Identifier for 'inplace_enabled' to use as internal '_custom' dictionary key,
 # or directly as a (temporary) attribute name if '_custom' is not provided:
-INPLACE_ENABLED_PLACEHOLDER = '_is_inplace'
+INPLACE_ENABLED_PLACEHOLDER = '_to_assign'
 
 
 def _inplace_enabled(operation_method):

cf/field.py

@@ -16836,9 +16836,14 @@ def regrids(self, dst, method, src_cyclic=None, dst_cyclic=None,
         # Construct new data from regridded sdst_dictections
         new_data = Data.reconstruct_sectioned_data(sections)
 
-        # Construct new field
-        f = _inplace_enabled_define_and_cleanup(self)
-
+        # Construct new field.
+        # Note: cannot call `_inplace_enabled_define_and_cleanup(self)` to apply this
+        # if-else logic (it deletes the decorator attribute so can only be used once)
+        if inplace:
+            f = self
+        else:
+            f = self.copy()
+
         # Update ancillary variables of new field
         #f._conform_ancillary_variables(src_axis_keys, keep_size_1=False)