diff -r 18c2753434f2 -r dd5b5f99940d mercurial/branchmap.py
--- a/mercurial/branchmap.py	Fri Mar 08 16:52:08 2024 +0100
+++ b/mercurial/branchmap.py	Fri Mar 08 16:49:06 2024 +0100
@@ -569,9 +569,6 @@
             closednodes=set(self._closednodes),
             verify_node=self._verify_node,
         )
-        # we copy will likely schedule a write anyway, but that does not seems
-        # to hurt to overschedule
-        other._dirty = self._dirty
         # also copy information about the current verification state
         other._verifiedbranches = set(self._verifiedbranches)
         return other