diff --git a/changelog.d/6-federation/fix-mls-client-assertions b/changelog.d/6-federation/fix-mls-client-assertions
new file mode 100644
index 00000000000..a86074bff84
--- /dev/null
+++ b/changelog.d/6-federation/fix-mls-client-assertions
@@ -0,0 +1 @@
+Fix assertion in testWelcomeNoKey
diff --git a/services/galley/test/integration/API/MLS.hs b/services/galley/test/integration/API/MLS.hs
index 39eb06605d4..dcc30d9c503 100644
--- a/services/galley/test/integration/API/MLS.hs
+++ b/services/galley/test/integration/API/MLS.hs
@@ -53,8 +53,7 @@ tests s =
     [ testGroup
         "Welcome"
         [ test s "local welcome" testLocalWelcome,
-          test s "local welcome (client with no public key)" testWelcomeNoKey,
-          test s "local welcome (client with no public key)" testWelcomeUnknownClient
+          test s "local welcome (client with no public key)" testWelcomeNoKey
         ],
       testGroup
         "Creation"
@@ -145,23 +144,10 @@ testWelcomeNoKey = do
         . paths ["mls", "welcome"]
         . zUser (qUnqualified (pUserId creator))
         . content "message/mls"
+        . zConn "conn"
         . bytes welcome
     )
-    !!! const 400 === statusCode
-
-testWelcomeUnknownClient :: TestM ()
-testWelcomeUnknownClient = do
-  MessagingSetup {..} <- aliceInvitesBob 1 def {createClients = DontCreateClients}
-
-  galley <- viewGalley
-  post
-    ( galley
-        . paths ["mls", "welcome"]
-        . zUser (qUnqualified (pUserId creator))
-        . content "message/mls"
-        . bytes welcome
-    )
-    !!! const 400 === statusCode
+    !!! const 404 === statusCode
 
 -- | Send a commit message, and assert that all participants see an event with
 -- the given list of new members.
@@ -264,7 +250,7 @@ testAddUserWithProteusClients = do
       participants@(_, [bob]) <- setupParticipants tmp def [2]
 
       -- and a non-MLS client
-      void $ takeLastPrekey >>= lift . addClient (pUserId bob)
+      void $ takeLastPrekey >>= lift . randomClient (qUnqualified (pUserId bob))
 
       pure participants
 
diff --git a/services/galley/test/integration/API/MLS/Util.hs b/services/galley/test/integration/API/MLS/Util.hs
index a34847971f3..25b2fade389 100644
--- a/services/galley/test/integration/API/MLS/Util.hs
+++ b/services/galley/test/integration/API/MLS/Util.hs
@@ -40,6 +40,7 @@ import Imports
 import System.FilePath
 import System.IO.Temp
 import System.Process
+import Test.QuickCheck (arbitrary, generate)
 import Test.Tasty.HUnit
 import TestSetup
 import Wire.API.Conversation
@@ -109,8 +110,8 @@ setupUserClient tmp doCreateClients usr = do
   lift $ do
     -- create client if requested
     c <- case doCreateClients of
-      DontCreateClients -> randomClient (qUnqualified usr) lpk
-      _ -> addClient usr lpk
+      DontCreateClients -> liftIO $ generate arbitrary
+      _ -> randomClient (qUnqualified usr) lpk
 
     let qcid =
           show (qUnqualified usr)
@@ -235,24 +236,6 @@ aliceInvitesBob numBobClients opts@SetupOptions {..} = withSystemTempDirectory "
         ..
       }
 
-addClient :: HasCallStack => Qualified UserId -> LastPrekey -> TestM ClientId
-addClient u lpk = do
-  let new = newClient PermanentClientType lpk
-
-  brig <- view tsBrig
-  c <-
-    responseJsonError
-      =<< post
-        ( brig
-            . paths ["i", "clients", toByteString' (qUnqualified u)]
-            . zConn "conn"
-            . queryItem "skip_reauth" "true"
-            . json new
-        )
-      <!! const 201 === statusCode
-
-  pure (clientId c)
-
 addKeyPackage :: HasCallStack => Qualified UserId -> ClientId -> RawMLS KeyPackage -> TestM ()
 addKeyPackage u c kp = do
   let update = defUpdateClient {updateClientMLSPublicKeys = Map.singleton Ed25519 (bcSignatureKey (kpCredential (rmValue kp)))}
diff --git a/services/galley/test/integration/API/Util.hs b/services/galley/test/integration/API/Util.hs
index c65997d6104..f72eb36c8e6 100644
--- a/services/galley/test/integration/API/Util.hs
+++ b/services/galley/test/integration/API/Util.hs
@@ -2004,7 +2004,12 @@ randomClientWithCaps :: HasCallStack => UserId -> LastPrekey -> Maybe (Set Clien
 randomClientWithCaps uid lk caps = do
   b <- view tsBrig
   resp <-
-    post (b . paths ["i", "clients", toByteString' uid] . json newClientBody)
+    post
+      ( b
+          . paths ["i", "clients", toByteString' uid]
+          . queryItem "skip_reauth" "true"
+          . json newClientBody
+      )
       <!! const rStatus === statusCode
   client <- responseJsonError resp
   return (clientId client)