diff -r 864f4ebe6a8d -r 6597255a4f94 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Mon May 03 12:34:41 2021 +0200
+++ b/mercurial/localrepo.py	Mon May 03 12:34:52 2021 +0200
@@ -739,6 +739,8 @@
 
     if requirementsmod.REVLOGV2_REQUIREMENT in requirements:
         features.add(repository.REPO_FEATURE_SIDE_DATA)
+        # the revlogv2 docket introduced race condition that we need to fix
+        features.discard(repository.REPO_FEATURE_STREAM_CLONE)
 
     # The cache vfs is used to manage cache files.
     cachevfs = vfsmod.vfs(cachepath, cacheaudited=True)