When the approval dialog setting is not set to "always on" and I send a mail to a group mail address for which I have a Kleopatra group definition and one of the certificates is not certified (not VS-NfD compliant) the security approval dialog should come up anyway, because there is a decision to be made.
This does not happen.
Setup after import of group definition:
With the following settings. Note that "always secure mails" is not set.
Mail is sent without notification.
Cross check, setting to always show dialog:
Warning for the not compliant key, after hitting "send" with same recipient: