Upgrading from 2.4.2 to 2.4.3 broke static password login

Hey folks,

I've got dovecot running via docker on version 2.4.2. Here's what my config extension looks like:

# auth_mechanisms = plain login
auth_verbose = yes

passdb static {
  password = %{env:USER_PASSWORD}
}

service lmtp {
   inet_listener lmtps {
     port = 31024
     ssl = no
   }
}

ssl_server_cert_file = /etc/dovecot/ssl/cert.pem
ssl_server_key_file = /etc/dovecot/ssl/key.pem
ssl = yes
auth_allow_cleartext = no

namespace inbox {
  type = private
  separator = /
  inbox = yes

  mailbox Drafts {
    special_use = \Drafts
    auto = subscribe
  }

  mailbox Junk {
    special_use = \Junk
    auto = create
  }

  mailbox spam {
    special_use = \Junk
    auto = no
  }

  mailbox Spam {
    special_use = \Junk
    auto = no
  }

  mailbox Trash {
    special_use = \Trash
    auto = subscribe
  }

  mailbox TRASH {
    special_use = \Trash
    auto = no
  }

  mailbox Sent {
    special_use = \Sent
    auto = subscribe
  }

  mailbox "Sent Mail" {
    special_use = \Sent
    auto = no
  }

  mailbox "Sent Messages" {
    special_use = \Sent
    auto = no
  }

  mailbox Archive {
    special_use = \Archive
    auto = create
  }

  mailbox "Archives" {
    special_use = \Archive
    auto = no
  }
}

I have env USER_PASSWORD defined in the format of {PLAIN}REDACTED

This has been humming along fine for a little while. I recently automatically upgraded to 2.4.3 which broke my ability to login via IMAP to retrieve emails (it also broke my local mail transport setup; it was unable to send emails). I could see the following messages in the logs:

Apr 27 11:12:09 auth(REDACTED,REDACTED,sasl:plain)<REDACTED>: Info: static: No password returned (and no nopassword)
Apr 27 11:12:11 imap-login: Info: Login aborted: Connection closed (auth failed, 1 attempts in 6 secs) (auth_failed): user=<REDACTED>, method=PLAIN, rip=REDACTED, lip=172.17.0.2, TLS, session=<REDACTED>

Downgrading back to 2.4.2 "fixed" the problem (I was able to login again; LMTP worked again). I didn't change my config extension between the upgrades.

I tried searching https://github.com/search?q=repo%3Adovecot%2Fcore+password&type=issues and I see a few related to passwords but nothing is really jumping out at me.

Help? I'm staying pinned on 2.4.2 for now but that's not a long term solution.