Mail drafts always become read when opened with manual seen set

Setting the manual seen, the mails present in the drafts folder are marked as views when opened

Steps to reproduce:

• select "manual seen" in the settings> Mail> Main
• set up an email in proofs to read (unseen)
• open the email

Expected behaviour:

• the mail is opened and the status does not change (remains unseen)

Actual behaviour:

• the mail is opened and the status also changes and becomes seen