diff --git a/.mypy-baseline.txt b/.mypy-baseline.txt
index 68d1cdd5f..12e169efd 100644
--- a/.mypy-baseline.txt
+++ b/.mypy-baseline.txt
@@ -2118,7 +2118,6 @@ src/paperless_mail/mail.py:0: error: Function is missing a return type annotatio
 src/paperless_mail/mail.py:0: error: Function is missing a return type annotation  [no-untyped-def]
 src/paperless_mail/mail.py:0: error: Function is missing a return type annotation  [no-untyped-def]
 src/paperless_mail/mail.py:0: error: Function is missing a return type annotation  [no-untyped-def]
-src/paperless_mail/mail.py:0: error: Function is missing a return type annotation  [no-untyped-def]
 src/paperless_mail/mail.py:0: error: Function is missing a type annotation for one or more arguments  [no-untyped-def]
 src/paperless_mail/mail.py:0: error: Function is missing a type annotation for one or more arguments  [no-untyped-def]
 src/paperless_mail/mail.py:0: error: Function is missing a type annotation for one or more arguments  [no-untyped-def]
diff --git a/src/paperless_mail/mail.py b/src/paperless_mail/mail.py
index ce7df5b7e..56eaefaad 100644
--- a/src/paperless_mail/mail.py
+++ b/src/paperless_mail/mail.py
@@ -536,7 +536,7 @@ class MailAccountHandler(LoggingMixin):
         self.log.debug(f"Processing mail account {account}")
 
         total_processed_files = 0
-        consumed_messages: set[tuple[str, str]] = set()
+        consumed_messages: set[tuple[str, str | None]] = set()
         try:
             with get_mailbox(
                 account.imap_server,
@@ -607,8 +607,8 @@ class MailAccountHandler(LoggingMixin):
         rule: MailRule,
         *,
         supports_gmail_labels: bool,
-        consumed_messages: set[tuple[str, str]],
-    ):
+        consumed_messages: set[tuple[str, str | None]],
+    ) -> int:
         folders = [rule.folder]
         # In case of MOVE, make sure also the destination exists
         if rule.action == MailRule.MailAction.MOVE:
@@ -655,7 +655,7 @@ class MailAccountHandler(LoggingMixin):
 
         mails_processed = 0
         total_processed_files = 0
-        rule_seen_messages: set[tuple[str, str]] = set()
+        rule_seen_messages: set[tuple[str, str | None]] = set()
 
         for message in messages:
             if TYPE_CHECKING:
diff --git a/src/paperless_mail/tests/test_mail.py b/src/paperless_mail/tests/test_mail.py
index 468b28906..7945087fc 100644
--- a/src/paperless_mail/tests/test_mail.py
+++ b/src/paperless_mail/tests/test_mail.py
@@ -863,7 +863,7 @@ class TestMail(
 
         self.assertEqual(len(self.mailMocker.bogus_mailbox.messages), 0)
 
-    def test_handle_mail_account_overlapping_rules_only_first_consumes(self):
+    def test_handle_mail_account_overlapping_rules_only_first_consumes(self) -> None:
         account = MailAccount.objects.create(
             name="test",
             imap_server="",
@@ -895,7 +895,7 @@ class TestMail(
         ]
         self.assertEqual(queued_rule.id, first_rule.id)
 
-    def test_handle_mail_account_skip_duplicate_uids_from_fetch(self):
+    def test_handle_mail_account_skip_duplicate_uids_from_fetch(self) -> None:
         account = MailAccount.objects.create(
             name="test",
             imap_server="",