mail keeps a draft open
When I quit mail, there is a blank draft open in the background.
MacBook Pro 15″, macOS 11.2
Question marked as
Ah, Mail>Preferences>Accounts>Your Account>Mailbox Behaviors, what path is Drafts Mailbox set to?
Setting it to an On My Mac Drafts box generally cures it.
Try setting to an On My Mac Box.