--- a/mercurial/cext/parsers.c	Wed Nov 24 05:00:06 2021 +0100
+++ b/mercurial/cext/parsers.c	Wed Nov 24 04:43:57 2021 +0100
@@ -450,14 +450,6 @@
 		              dirstate_flag_has_meaningful_data |
 		              dirstate_flag_has_mtime);
 	}
-	if (t->flags & dirstate_flag_mtime_second_ambiguous) {
-		/* The current code is not able to do the more subtle comparison
-		 * that the MTIME_SECOND_AMBIGUOUS requires. So we ignore the
-		 * mtime */
-		t->flags &= ~(dirstate_flag_mtime_second_ambiguous |
-		              dirstate_flag_has_meaningful_data |
-		              dirstate_flag_has_mtime);
-	}
 	t->mode = 0;
 	if (t->flags & dirstate_flag_has_meaningful_data) {
 		if (t->flags & dirstate_flag_mode_exec_perm) {

--- a/mercurial/pure/parsers.py	Wed Nov 24 05:00:06 2021 +0100
+++ b/mercurial/pure/parsers.py	Wed Nov 24 04:43:57 2021 +0100
@@ -149,10 +149,6 @@
         """Build a new DirstateItem object from V2 data"""
         has_mode_size = bool(flags & DIRSTATE_V2_HAS_MODE_AND_SIZE)
         has_meaningful_mtime = bool(flags & DIRSTATE_V2_HAS_MTIME)
-        if flags & DIRSTATE_V2_MTIME_SECOND_AMBIGUOUS:
-            # The current code is not able to do the more subtle comparison that the
-            # MTIME_SECOND_AMBIGUOUS requires. So we ignore the mtime
-            has_meaningful_mtime = False
         mode = None
 
         if flags & +DIRSTATE_V2_EXPECTED_STATE_IS_MODIFIED:
@@ -179,13 +175,15 @@
                 mode |= stat.S_IFLNK
             else:
                 mode |= stat.S_IFREG
+
+        second_ambiguous = flags & DIRSTATE_V2_MTIME_SECOND_AMBIGUOUS
         return cls(
             wc_tracked=bool(flags & DIRSTATE_V2_WDIR_TRACKED),
             p1_tracked=bool(flags & DIRSTATE_V2_P1_TRACKED),
             p2_info=bool(flags & DIRSTATE_V2_P2_INFO),
             has_meaningful_data=has_mode_size,
             has_meaningful_mtime=has_meaningful_mtime,
-            parentfiledata=(mode, size, (mtime_s, mtime_ns, False)),
+            parentfiledata=(mode, size, (mtime_s, mtime_ns, second_ambiguous)),
             fallback_exec=fallback_exec,
             fallback_symlink=fallback_symlink,
         )

--- a/rust/hg-core/src/dirstate_tree/on_disk.rs	Wed Nov 24 05:00:06 2021 +0100
+++ b/rust/hg-core/src/dirstate_tree/on_disk.rs	Wed Nov 24 04:43:57 2021 +0100
@@ -371,11 +371,12 @@
         let mtime = if self.flags().contains(Flags::HAS_MTIME)
             && !self.flags().contains(Flags::DIRECTORY)
             && !self.flags().contains(Flags::EXPECTED_STATE_IS_MODIFIED)
-            // The current code is not able to do the more subtle comparison that the
-            // MTIME_SECOND_AMBIGUOUS requires. So we ignore the mtime
-            && !self.flags().contains(Flags::MTIME_SECOND_AMBIGUOUS)
         {
-            Some(self.mtime.try_into()?)
+            let mut m: TruncatedTimestamp = self.mtime.try_into()?;
+            if self.flags().contains(Flags::MTIME_SECOND_AMBIGUOUS) {
+                m.second_ambiguous = true;
+            }
+            Some(m)
         } else {
             None
         };