diff --git a/hOpenPGP.cabal b/hOpenPGP.cabal
--- a/hOpenPGP.cabal
+++ b/hOpenPGP.cabal
@@ -1,6 +1,6 @@
 Cabal-version:       3.4
 Name:                hOpenPGP
-Version:             3.7.4
+Version:             3.7.4.1
 Synopsis:            native Haskell implementation of OpenPGP (RFC9580)
 Description:         native Haskell implementation of OpenPGP (RFC9580), with some backwards compatibility
 Homepage:            https://salsa.debian.org/clint/hOpenPGP
@@ -346,4 +346,4 @@
 source-repository this
   type:     git
   location: https://salsa.debian.org/clint/hOpenPGP.git
-  tag:      v3.7.4
+  tag:      v3.7.4.1
diff --git a/tests/Tests/Encryption.hs b/tests/Tests/Encryption.hs
--- a/tests/Tests/Encryption.hs
+++ b/tests/Tests/Encryption.hs
@@ -6,6 +6,7 @@
 {-# LANGUAGE MonoLocalBinds #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
 
 module Tests.Encryption (encryptionAndCompressionTests) where
 
@@ -112,6 +113,7 @@
 import Codec.Encryption.OpenPGP.Internal
     ( checksum16BE
     , point2MBS
+    , intToFixedWidth
     )
 import Codec.Encryption.OpenPGP.Internal.HOBlockCipher
     ( HOBlockCipher (..)
@@ -2516,11 +2518,11 @@
             ( PKESKPayloadV3Packet
                     (PKESKPayloadV3 _ _ X25519 (ephMPI NE.:| _))
                 ) -> do
-                let ephemeralBytes = i2osp (unMPI ephMPI)
-                assertEqual
-                    "PKESKv3 v6 X25519 ephemeral must be raw 32 bytes (no 0x40 prefix)"
-                    32
-                    (B.length ephemeralBytes)
+                case intToFixedWidth @32 (unMPI ephMPI) of
+                    Nothing ->
+                        assertFailure
+                            "ephemeral exceeds 32 octets — stray 0x40 prefix leaked into the MPI"
+                    Just _ -> pure ()
         Right other ->
             assertFailure
                 ("Expected PKESKPayloadV3 with X25519, got " ++ show other)