Template sensor - "availability": using "this.attributes" or state_attr() for this entity

Consider these template sensors (examples are synthetic):

template:
  - binary_sensor:

      - name: testing_availability_from_attributes_3
        state: on
        attributes:
          monitored_entity_id: 'sensor.processor_use'
          some_attr: >-
            {% set MONITORED_ENTITY_ID = state_attr('binary_sensor.testing_availability_from_attributes_3','monitored_entity_id') -%}
            {{ MONITORED_ENTITY_ID is not none }}

      - name: testing_availability_from_attributes_4
        state: on
        attributes:
          monitored_entity_id: 'sensor.processor_use'
          some_attr: &ref_availability_full_4 >-
            {% set MONITORED_ENTITY_ID = state_attr('binary_sensor.testing_availability_from_attributes_4','monitored_entity_id') -%}
            {{ MONITORED_ENTITY_ID is not none }}
        availability: *ref_availability_full_4

      - name: testing_availability_from_attributes_5
        state: on
        attributes:
          monitored_entity_id: 'sensor.processor_use'
          some_attr: &ref_availability_this >-
            {{ this.attributes['monitored_entity_id'] is defined }}

      - name: testing_availability_from_attributes_6
        state: on
        attributes:
          monitored_entity_id: 'sensor.processor_use'
          some_attr: *ref_availability_this
        availability: *ref_availability_this

And these output:

Seems that I cannot use neither “this.attributes” nor “state_attr()” for the same entity.
In both cases the “availability” becomes “false”.
Is it an expected behaviour?

As I said, these are synthetic examples.
I may not refer to “state_attr()” or “this.attributes” in “availability” - instead I should use a “sensor.processor_use” explicitly for processing (like “if a state of that entity is not a number → then unavailable”).

I faced the issue when I tried to define “availability” using “this.attributes[…]” - for using this expression as a yaml anchor for other sensors.
It always gave “false” for “availability”, so I tested with “state_attr()” and got same results as well.

Seems that this may be explained by an order of processing:
from here:

which possibly means: “availability” should not be defined based on the same entity’s attributes.