This question already has an answer here:
Following our upgrade to CiviCRM 5.9.0, the 'from' address for event registration confirmations has changed to "email@example.com"
It should be ""Ian Foster" " - and this is what still appears in the list of 'From' addresses in CiviCRM settings.
I've looked at contact ID 7306, in case it is a contact ID, and they have no significance in our system.
Baffled! Any thoughts? Thank you.