Version 5.5.7 fails to activate heating with AttributeError: 'dict' object has no attribute 'async_simple_render'

[FrankTub]

I upgraded yesterday from 5.5.4 to 5.5.7 and today my heating wasn't activated as expected. Sadly I don't have a trace to help pinpoint the exact root cause. The error in my logs:

Logger: homeassistant.components.automation.badkamer_vloerverwarming
Source: components/automation/__init__.py:803
integration: Automation ([documentation](https://www.home-assistant.io/integrations/automation), [issues](https://github.com/home-assistant/core/issues?q=is%3Aissue+is%3Aopen+label%3A%22integration%3A+automation%22))
First occurred: 5:50:00 PM (1 occurrence)
Last logged: 5:50:00 PM

While executing automation automation.badkamer_vloerverwarming
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/automation/__init__.py", line 803, in async_trigger
    return await self.action_script.async_run(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        variables, trigger_context, started_action
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1837, in async_run
    return await asyncio.shield(create_eager_task(run.async_run()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1331, in async_run
    return await super().async_run()
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 460, in async_run
    await self._async_step(log_exceptions=False)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 526, in _async_step
    self._handle_exception(
    ~~~~~~~~~~~~~~~~~~~~~~^
        ex, continue_on_error, self._log_exceptions or log_exceptions
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 556, in _handle_exception
    raise exception
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 739, in _async_step_choose
    await self._async_run_script(choose_data["default"])
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 636, in _async_run_script
    result = await self._async_run_long_action(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<6 lines>...
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 624, in _async_run_long_action
    return await long_task
           ^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1837, in async_run
    return await asyncio.shield(create_eager_task(run.async_run()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 460, in async_run
    await self._async_step(log_exceptions=False)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 526, in _async_step
    self._handle_exception(
    ~~~~~~~~~~~~~~~~~~~~~~^
        ex, continue_on_error, self._log_exceptions or log_exceptions
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 556, in _handle_exception
    raise exception
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 780, in _async_step_if
    await self._async_run_script(if_data["if_else"])
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 636, in _async_run_script
    result = await self._async_run_long_action(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<6 lines>...
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 624, in _async_run_long_action
    return await long_task
           ^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1837, in async_run
    return await asyncio.shield(create_eager_task(run.async_run()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 460, in async_run
    await self._async_step(log_exceptions=False)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 526, in _async_step
    self._handle_exception(
    ~~~~~~~~~~~~~~~~~~~~~~^
        ex, continue_on_error, self._log_exceptions or log_exceptions
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 556, in _handle_exception
    raise exception
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 774, in _async_step_if
    await self._async_run_script(if_data["if_then"])
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 636, in _async_run_script
    result = await self._async_run_long_action(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<6 lines>...
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 624, in _async_run_long_action
    return await long_task
           ^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1837, in async_run
    return await asyncio.shield(create_eager_task(run.async_run()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 460, in async_run
    await self._async_step(log_exceptions=False)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 526, in _async_step
    self._handle_exception(
    ~~~~~~~~~~~~~~~~~~~~~~^
        ex, continue_on_error, self._log_exceptions or log_exceptions
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 556, in _handle_exception
    raise exception
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/trace.py", line 283, in async_wrapper
    await func(*args)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 941, in _async_step_repeat
    await self._async_do_step_repeat()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 821, in _async_do_step_repeat
    await async_run_sequence(iteration, extra_msg)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 803, in async_run_sequence
    await self._async_run_script(script)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 636, in _async_run_script
    result = await self._async_run_long_action(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<6 lines>...
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 624, in _async_run_long_action
    return await long_task
           ^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 1837, in async_run
    return await asyncio.shield(create_eager_task(run.async_run()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 460, in async_run
    await self._async_step(log_exceptions=False)
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 526, in _async_step
    self._handle_exception(
    ~~~~~~~~~~~~~~~~~~~~~~^
        ex, continue_on_error, self._log_exceptions or log_exceptions
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 556, in _handle_exception
    raise exception
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 975, in _async_step_variables
    self._action[CONF_VARIABLES].async_simple_render(self._variables)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'dict' object has no attribute 'async_simple_render'

And less detailed it also shows:

Badkamer vloerverwarming: Choose at step 4: default: If at step 8: If at step 2: Repeat at step 1: Error executing script. Unexpected error for variables at pos 1: 'dict' object has no attribute 'async_simple_render'
Badkamer vloerverwarming: Choose at step 4: default: If at step 8: If at step 2: Error executing script. Unexpected error for repeat at pos 1: 'dict' object has no attribute 'async_simple_render'
Badkamer vloerverwarming: Choose at step 4: default: If at step 8: Error executing script. Unexpected error for if at pos 2: 'dict' object has no attribute 'async_simple_render'
Badkamer vloerverwarming: Choose at step 4: default: Error executing script. Unexpected error for if at pos 8: 'dict' object has no attribute 'async_simple_render'
Badkamer vloerverwarming: Error executing script. Unexpected error for choose at pos 4: 'dict' object has no attribute 'async_simple_render'
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 524, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 975, in _async_step_variables
    self._action[CONF_VARIABLES].async_simple_render(self._variables)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'dict' object has no attribute 'async_simple_render'