--- a/mercurial/branchmap.py	Fri Oct 11 00:56:20 2024 -0400
+++ b/mercurial/branchmap.py	Tue Oct 01 12:29:10 2024 +0200
@@ -1070,6 +1070,7 @@
         for branch, heads in self._entries.items():
             if heads == topo_heads:
                 self._pure_topo_branch = branch
+                self._state = STATE_DIRTY
                 break