TYPO3 Core

As far as I understand this, this has nothing to do with the not working overrides finisher. Therefore I removed the relation to that issue.

The issue is, that you can use the value in a field from the form (e.g. {email-1}) to be the target email address in sender, recipients, cc, bcc and reply to, when you define the form as yaml file (and I guess also in the editor in the backend). If you try to override this finisher, the email field is validated to be required AND to be an email address. So the fields behave different to the configuration.

A possible solution would be to made the fields normal input fields in TYPO3 12 again and remove the email validator in TYPO3 11.

I agree with Dennis, this behaviour should be consistent and should also be available in TYPO3 11

This should be a must-have, as the EmailToSender finisher can no longer be used in a meaningful way if you override the finishers in the backend. Or is there a workaround for this?
Since "recipients" is a mandatory field, you also can't leave it empty in the backend to cause a fallback to the YAML configuration (this works for replyToRecipients).

Maybe this could be changed to a v12 issue to get more attention? (I noticed it with TYPO3 12.4.7)

In my opinion, this is also an absolute must-have for TYPO3 11!
I had to modify the EmailToSender.yaml in the core to use the feature, which is actually an absolute no-go.

Therefore, a quick fix would be great!