There’s a rather disturbing article at https://insulinnation.com/treatment/319050/ that tells of someone who was changing the reservoir in their Medtronic pump (looks like a 630 or 670). They inadvertently didn’t finish all the steps.
The pump quietly waited for them to complete the steps, and meanwhile blocked all the CGM alerts from the pump. All night. They went all night without insulin delivery and there were no CGM alerts; the pump was just sitting on the Fill Reservoir screen.
My first comment is Yikes! My second comment is the same as the first.