--- a/mercurial/cext/parsers.c	Wed Nov 24 04:51:05 2021 +0100
+++ b/mercurial/cext/parsers.c	Wed Nov 24 04:59:48 2021 +0100
@@ -269,7 +269,8 @@
 	} else if (!(self->flags & dirstate_flag_has_mtime) ||
 	           !(self->flags & dirstate_flag_p1_tracked) ||
 	           !(self->flags & dirstate_flag_wc_tracked) ||
-	           (self->flags & dirstate_flag_p2_info)) {
+	           (self->flags & dirstate_flag_p2_info) ||
+	           (self->flags & dirstate_flag_mtime_second_ambiguous)) {
 		return ambiguous_time;
 	} else {
 		return self->mtime_s;

--- a/mercurial/pure/parsers.py	Wed Nov 24 04:51:05 2021 +0100
+++ b/mercurial/pure/parsers.py	Wed Nov 24 04:59:48 2021 +0100
@@ -551,6 +551,8 @@
             return AMBIGUOUS_TIME
         elif not self._p1_tracked:
             return AMBIGUOUS_TIME
+        elif self._mtime_second_ambiguous:
+            return AMBIGUOUS_TIME
         else:
             return self._mtime_s
 

--- a/rust/hg-core/src/dirstate/entry.rs	Wed Nov 24 04:51:05 2021 +0100
+++ b/rust/hg-core/src/dirstate/entry.rs	Wed Nov 24 04:59:48 2021 +0100
@@ -454,7 +454,11 @@
         } else if !self.flags.contains(Flags::P1_TRACKED) {
             MTIME_UNSET
         } else if let Some(mtime) = self.mtime {
-            i32::try_from(mtime.truncated_seconds()).unwrap()
+            if mtime.second_ambiguous {
+                MTIME_UNSET
+            } else {
+                i32::try_from(mtime.truncated_seconds()).unwrap()
+            }
         } else {
             MTIME_UNSET
         }