Currently the two fields seem to be treated as one and the same (see linked issue). The following usecase should in this case pass:
1. A user shows up to the RA with a CSR which contain an e-mail in the subject DN
2. Whether the mail is sourced from the CSR or entered manually, there will be a field to enter/modify/view the mail value
3. At the bottom of the page the user may specify the EE-email to send notification to. This should not in any way be affected by the above, or affect the subject DN if changed.