What temp does the machine show for the steam boiler when this happens
I had the same issue and it was the temp sensor on the boiler.
It's an easy fix, you need to email acs with the vid, they will ask you your steam boiler settings, potentially get you to change them,
If it is the temp sensor, then you need to remove the back panel, the counter weight and the sensor is undo with a spanner, when put back in use PTFE tape and the wie is on a connector.
