Two reasons why that cannot be my fix:
- I am not using bulk notifications
- I am already on p3
UPDATE: When I change the notification plugin from asciimail to mail it seems to work. Still verifying, but the issue seems to be in the asciimail plugin.
P.S.: I clarified my former post regarding the sender address: It is not the address I set in the appliance as fallback, but rather the (builtin?) fallback, that goes like $SITE@$HOSTNAME. In my use case that is a major problem as the host has an internal domain which cannot be routed on the internet.