Since upgrade to 28.0.1 Birthday calendars keep sending notification mails

Since upgrading Nextcloud to version 28.0.1 I keep receiving mails from Birthday calendars. The mail refers to the notifications settings for the user to make changes but I see no option that makes reference to Birthday calendar mail notifications.

Is there something I am missing or is there a general setting somewhere else?

Thanks for your help.

best,
peter

Same behaviour here after update to 28.0.1 There is no switch to deactivate the notifications global or individually.

Best regards
DZ