diff --git a/cabal-install/Distribution/Client/FetchUtils.hs b/cabal-install/Distribution/Client/FetchUtils.hs
index ae2e2717966214ead720529870dbadaaeada29e6..1099c91d72a1197153fe3eeefe258011d736f04d 100644
--- a/cabal-install/Distribution/Client/FetchUtils.hs
+++ b/cabal-install/Distribution/Client/FetchUtils.hs
@@ -162,7 +162,7 @@ fetchPackage verbosity repoCtxt loc = case loc of
 -- | Fetch a repo package if we don't have it already.
 --
 fetchRepoTarball :: Verbosity -> RepoContext -> Repo -> PackageId -> IO FilePath
-fetchRepoTarball verbosity repoCtxt repo pkgid = do
+fetchRepoTarball verbosity' repoCtxt repo pkgid = do
   fetched <- doesFileExist (packageFile repo pkgid)
   if fetched
     then do info verbosity $ display pkgid ++ " has already been downloaded."
@@ -171,9 +171,10 @@ fetchRepoTarball verbosity repoCtxt repo pkgid = do
             res <- downloadRepoPackage
             progressMessage verbosity ProgressDownloaded (display pkgid)
             return res
-
-
   where
+    -- whether we download or not is non-deterministic
+    verbosity' = verboseUnmarkOutput verbosity'
+
     downloadRepoPackage = case repo of
       RepoLocal{..} -> return (packageFile repo pkgid)
 
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-external.test.hs b/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-external.test.hs
index d07a96756ab47d86821facc8bad699604159d979..3e9936d8565d6566e0654ff55c8fac1313113357 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-external.test.hs
+++ b/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-external.test.hs
@@ -2,7 +2,6 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnless =<< ghcVersionIs (>= mkVersion [8,1])
-    skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
     withProjectFile "cabal.external.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-internal.test.hs b/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-internal.test.hs
index 8aa865addb9a8f9324c9895cad369a603717c679..ed5c0978c79a8b91e639e70483e037640c4e23c4 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-internal.test.hs
+++ b/cabal-testsuite/PackageTests/Backpack/Includes2/cabal-internal.test.hs
@@ -2,7 +2,6 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnless =<< ghcVersionIs (>= mkVersion [8,1])
-    skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
     withProjectFile "cabal.internal.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-external.test.hs b/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-external.test.hs
index 1e247c8ce64b54406fa6b72595c5a0b05039c579..29401091617475b52728bc3f9017f44ac741d055 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-external.test.hs
+++ b/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-external.test.hs
@@ -2,7 +2,6 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnless =<< ghcVersionIs (>= mkVersion [8,1])
-    skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
     withProjectFile "cabal.external.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
diff --git a/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-internal.test.hs b/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-internal.test.hs
index ebf058911192c64e799b26affea8f8b469ab6979..56c49c6e97fea76fafc27579e61a519fd8d92860 100644
--- a/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-internal.test.hs
+++ b/cabal-testsuite/PackageTests/Backpack/Includes3/cabal-internal.test.hs
@@ -2,7 +2,6 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnless =<< ghcVersionIs (>= mkVersion [8,1])
-    skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
     withProjectFile "cabal.internal.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
diff --git a/cabal-testsuite/PackageTests/Backpack/bkpcabal01/cabal.test.hs b/cabal-testsuite/PackageTests/Backpack/bkpcabal01/cabal.test.hs
index ae7e000f4c429b5872c711afe3b21b902d050c6c..08cbbd3c8078375f5d4766ba810abedcde0b210c 100644
--- a/cabal-testsuite/PackageTests/Backpack/bkpcabal01/cabal.test.hs
+++ b/cabal-testsuite/PackageTests/Backpack/bkpcabal01/cabal.test.hs
@@ -2,5 +2,4 @@ import Test.Cabal.Prelude
 main = cabalTest $ do
     -- GHC 8.2.2 had a regression ("unknown package: hole"), see also #4908
     skipUnless =<< ghcVersionIs (\v -> v >= mkVersion [8,2] && v /= mkVersion [8,2,2])
-    skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
     cabal "v2-build" ["all"]
diff --git a/cabal-testsuite/PackageTests/Regression/T5309/cabal.test.hs b/cabal-testsuite/PackageTests/Regression/T5309/cabal.test.hs
index 71f5f7a9b3e55e0dd5cfcddc07f32e5712bbe0e0..c7d8b1760da73b8db9a72610120cbc0921b86a33 100644
--- a/cabal-testsuite/PackageTests/Regression/T5309/cabal.test.hs
+++ b/cabal-testsuite/PackageTests/Regression/T5309/cabal.test.hs
@@ -1,6 +1,5 @@
 import Test.Cabal.Prelude
 main = cabalTest $ do
-  skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
   cabal "v2-build" ["all"]
   cabal "v2-test"  ["all"]
   cabal "v2-bench" ["all"]
diff --git a/cabal-testsuite/PackageTests/Regression/T5677/cabal.test.hs b/cabal-testsuite/PackageTests/Regression/T5677/cabal.test.hs
index 133f492145797d0741a8108fa751d65bd3d1d7bc..cf2a0b01cda6aabe99a5480bcc3b7f50a0b9a857 100644
--- a/cabal-testsuite/PackageTests/Regression/T5677/cabal.test.hs
+++ b/cabal-testsuite/PackageTests/Regression/T5677/cabal.test.hs
@@ -2,5 +2,4 @@ import Test.Cabal.Prelude
 main = cabalTest $ do
   -- -Wmissing-export-lists is new in 8.4.
   skipUnless =<< ghcVersionIs (>= mkVersion [8,3])
-  skipIf =<< isWindows -- TODO: https://github.com/haskell/cabal/issues/6271
   cabal "v2-build" ["all"]