Use updated task, instead of original, non-merged included_file._task (#39762)

* Used updated task, instead of original, non-merged included_file._task. Fixes #39637

* Add changelog entry

changelogs/fragments/includes.yaml

@@ -14,3 +14,4 @@ bugfixes:
 - dynamic includes - Allow inheriting attributes from static parents (https://github.com/ansible/ansible/pull/38827)
 - include_role/import_role - improved performance and recursion depth (https://github.com/ansible/ansible/pull/36470)
 - include_role/import_role - Fix parameter templating (https://github.com/ansible/ansible/pull/36372)
+- dynamic includes - Use the copied and merged task for calculating task vars (https://github.com/ansible/ansible/pull/39762)

lib/ansible/plugins/strategy/linear.py

@@ -363,7 +363,7 @@ class StrategyModule(StrategyBase):
                             for new_block in new_blocks:
                                 task_vars = self._variable_manager.get_vars(
                                     play=iterator._play,
-                                    task=included_file._task,
+                                    task=new_block._parent
                                 )
                                 display.debug("filtering new block on tags")
                                 final_block = new_block.filter_tagged_tasks(play_context, task_vars)