I checked on a new iOS 15 phone with latest v4 app version. I found my notifications for charge start and end turned off. I have seen these notifications turn themselves off in the past, so this won't be the first occurrence - iirc last time it seemed to be following the account rather than the device or car.
I've not charged since so I'm not sure if thats it sorted and the problem with no notifications has affected multiple drivers, different accounts, same car, different generations of phone and apps. But having notifications turned off is certainly not going to help matters.