diff -r 51aadc0d0da2 -r 55ef17ec8e59 mercurial/obsutil.py
--- a/mercurial/obsutil.py	Thu Jul 06 14:52:34 2017 +0200
+++ b/mercurial/obsutil.py	Thu Jul 06 14:53:48 2017 +0200
@@ -309,6 +309,7 @@
 EFFECTFLAGFIELD = "ef1"
 
 DESCCHANGED = 1 << 0 # action changed the description
+USERCHANGED = 1 << 4 # the user changed
 
 def geteffectflag(relation):
     """ From an obs-marker relation, compute what changed between the
@@ -323,6 +324,10 @@
         if changectx.description() != source.description():
             effects |= DESCCHANGED
 
+        # Check if user has changed
+        if changectx.user() != source.user():
+            effects |= USERCHANGED
+
     return effects
 
 def getobsoleted(repo, tr):