Integration not updating values until I reload the integration

[EinSchwerd]

The integration regularly stops updating values until I reload it. I see the following exceptions in the log:
`
This error originated from a custom integration.

Logger: homeassistant
Source: custom_components/bureau_of_meteorology/sensor.py:247
integration: Bureau of Meteorology (documentation, issues)
First occurred: 6 February 2025 at 19:07:10 (153 occurrences)
Last logged: 07:43:03

Error doing job: Task exception was never retrieved (None)
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1552, in _async_process_registry_update_or_remove
self.async_write_ha_state()
~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1023, in async_write_ha_state
self._async_write_ha_state()
~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1148, in _async_write_ha_state
self.__async_calculate_state()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1089, in __async_calculate_state
if extra_state_attributes := self.extra_state_attributes:
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/config/custom_components/bureau_of_meteorology/sensor.py", line 247, in extra_state_attributes
attr["time_observed"] = iso8601.parse_date(self.collector.observations_data["data"][self.sensor_name]["time"]).astimezone(tzinfo).isoformat()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
TypeError: 'NoneType' object is not subscriptable
`

and

'Logger: homeassistant.components.sensor
Source: helpers/entity_platform.py:609
integration: Sensor (documentation, issues)
First occurred: 6 February 2025 at 19:06:49 (2 occurrences)
Last logged: 6 February 2025 at 19:06:49

Error adding entity sensor.woronora_heights_max_temp for domain sensor with platform bureau_of_meteorology
Error adding entity sensor.woronora_heights_min_temp for domain sensor with platform bureau_of_meteorology
Traceback (most recent call last):
File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 609, in _async_add_entities
await coro
File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 928, in _async_add_entity
await entity.add_to_platform_finish()
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1383, in add_to_platform_finish
await self.async_added_to_hass()
File "/config/custom_components/bureau_of_meteorology/sensor.py", line 199, in async_added_to_hass
self._update_callback()
~~~~~~~~~~~~~~~~~~~~~^^
File "/config/custom_components/bureau_of_meteorology/sensor.py", line 203, in _update_callback
self.async_write_ha_state()
~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1023, in async_write_ha_state
self._async_write_ha_state()
~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1148, in _async_write_ha_state
self.__async_calculate_state()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1089, in __async_calculate_state
if extra_state_attributes := self.extra_state_attributes:
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/config/custom_components/bureau_of_meteorology/sensor.py", line 247, in extra_state_attributes
attr["time_observed"] = iso8601.parse_date(self.collector.observations_data["data"][self.sensor_name]["time"]).astimezone(tzinfo).isoformat()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
TypeError: 'NoneType' object is not subscriptable'