Assertion error

[FransHalsjes]

unning the miele integration with HA 115 gives:
Logger: homeassistant
Source: helpers/entity.py:438
First occurred: 12:26:14 (7 occurrences)
Last logged: 12:26:44

Error doing job: Task exception was never retrieved
Traceback (most recent call last):
File "/home/homeassistant/.homeassistant/custom_components/miele/init.py", line 148, in refresh_devices
platform.update_device_state()
File "/home/homeassistant/.homeassistant/custom_components/miele/sensor.py", line 72, in update_device_state
device.async_schedule_update_ha_state(True)
File "/srv/homeassistant/lib/python3.7/site-packages/homeassistant/helpers/entity.py", line 438, in async_schedule_update_ha_state
assert self.hass is not None
AssertionError

several times per second.