diff --git a/Bugzilla/Util.pm b/Bugzilla/Util.pm
index 8a45e98591..8da02640a1 100644
--- a/Bugzilla/Util.pm
+++ b/Bugzilla/Util.pm
@@ -649,25 +649,26 @@ sub time_ago {
 
   # DateTime object or seconds
   my $ss = ref($param) ? time() - $param->epoch : $param;
-  my $mm = round($ss / 60);
-  my $hh = round($ss / (60 * 60));
-  my $dd = round($ss / (60 * 60 * 24));
+  # Use floor for intermediate calculations to avoid rounding issues
+  my $mm = floor($ss / 60);
+  my $hh = floor($ss / (60 * 60));
+  my $dd = floor($ss / (60 * 60 * 24));
   # They are not the best definition of month and year,
   # but they should be good enough to be used here.
-  my $mo = round($ss / (60 * 60 * 24 * 30));
-  my $yy = round($ss / (60 * 60 * 24 * 365.2422));
+  my $mo = floor($ss / (60 * 60 * 24 * 30));
+  my $yy = floor($ss / (60 * 60 * 24 * 365.2422));
 
   return 'Just now'           if $ss < 10;
   return $ss . ' seconds ago' if $ss < 45;
-  return '1 minute ago'       if $ss < 90;
+  return '1 minute ago'       if $mm < 2;
   return $mm . ' minutes ago' if $mm < 45;
-  return '1 hour ago'         if $mm < 90;
+  return '1 hour ago'         if $hh < 2;
   return $hh . ' hours ago'   if $hh < 24;
-  return '1 day ago'          if $hh < 36;
+  return '1 day ago'          if $dd < 2;
   return $dd . ' days ago'    if $dd < 30;
-  return '1 month ago'        if $dd < 45;
+  return '1 month ago'        if $mo < 2;
   return $mo . ' months ago'  if $mo < 12;
-  return '1 year ago'         if $mo < 18;
+  return '1 year ago'         if $yy < 2;
   return $yy . ' years ago';
 }
 
@@ -976,7 +977,7 @@ sub extract_nicks {
 
 # This routine is used to determine the latest versions for a
 # given product from an external system. We need to fail gracefully
-# if the external system is down for any reason. If the call fails, 
+# if the external system is down for any reason. If the call fails,
 # then return undefined and let the caller decide what to do.
 sub fetch_product_versions {
   my ($product) = @_;
diff --git a/js/util.js b/js/util.js
index b74e2ee03d..d31e67779d 100644
--- a/js/util.js
+++ b/js/util.js
@@ -339,34 +339,35 @@ function bz_toggleClass(anElement, aClass) {
     anElement?.classList.toggle(aClass);
 }
 
-/* Returns a string representation of a duration.
- *
- * @param ss   Duration in seconds
- * or
- * @param date Date object
+/**
+ * Returns a string representation of a duration.
+ * @param {number | Date} param Duration in seconds or a Date object.
+ * @returns {string} Human-readable time ago string.
  */
-function timeAgo(param) {
-    var ss = param.constructor === Date ? Math.round((new Date() - param) / 1000) : param;
-    var mm = Math.round(ss / 60),
-        hh = Math.round(ss / (60 * 60)),
-        dd = Math.round(ss / (60 * 60 * 24)),
-        // They are not the best definition of month and year,
-        // but they should be good enough to be used here.
-        mo = Math.round(ss / (60 * 60 * 24 * 30)),
-        yy = Math.round(ss / (60 * 60 * 24 * 365.2422));
+const timeAgo = (param) => {
+    const ss = param.constructor === Date ? Math.round((new Date() - param) / 1000) : param;
+    // Use Math.floor for intermediate calculations to avoid rounding issues
+    const mm = Math.floor(ss / 60);
+    const hh = Math.floor(ss / (60 * 60));
+    const dd = Math.floor(ss / (60 * 60 * 24));
+    // They are not the best definition of month and year,
+    // but they should be good enough to be used here.
+    const mo = Math.floor(ss / (60 * 60 * 24 * 30));
+    const yy = Math.floor(ss / (60 * 60 * 24 * 365.2422));
+
     if (ss < 10) return 'Just now';
-    if (ss < 45) return ss + ' seconds ago';
-    if (ss < 90) return '1 minute ago';
-    if (mm < 45) return mm + ' minutes ago';
-    if (mm < 90) return '1 hour ago';
-    if (hh < 24) return hh + ' hours ago';
-    if (hh < 36) return '1 day ago';
-    if (dd < 30) return dd + ' days ago';
-    if (dd < 45) return '1 month ago';
-    if (mo < 12) return mo + ' months ago';
-    if (mo < 18) return '1 year ago';
-    return yy + ' years ago';
-}
+    if (ss < 45) return `${ss} seconds ago`;
+    if (mm < 2) return '1 minute ago';
+    if (mm < 45) return `${mm} minutes ago`;
+    if (hh < 2) return '1 hour ago';
+    if (hh < 24) return `${hh} hours ago`;
+    if (dd < 2) return '1 day ago';
+    if (dd < 30) return `${dd} days ago`;
+    if (mo < 2) return '1 month ago';
+    if (mo < 12) return `${mo} months ago`;
+    if (yy < 2) return '1 year ago';
+    return `${yy} years ago`;
+};
 
 /**
  * Format the given date as Bugzilla’s standard date format.
diff --git a/t/007util.t b/t/007util.t
index 2e640ae6f9..a248520554 100644
--- a/t/007util.t
+++ b/t/007util.t
@@ -15,7 +15,7 @@ use warnings;
 
 use lib qw(. lib local/lib/perl5 t);
 use Support::Files;
-use Test::More tests => 20;
+use Test::More tests => 52;
 use DateTime;
 
 BEGIN {
@@ -114,3 +114,56 @@ my ($removed, $added) = diff_arrays(\@old_array, \@new_array);
 is_deeply($removed, [qw(gamma alpha gamma)],
   'diff_array(\@old, \@new) (check removal)');
 is_deeply($added, [qw(delta)], 'diff_array(\@old, \@new) (check addition)');
+
+# time_ago():
+# Test with seconds
+is(time_ago(5), 'Just now', 'time_ago(5) returns "Just now"');
+is(time_ago(9), 'Just now', 'time_ago(9) returns "Just now"');
+is(time_ago(10), '10 seconds ago', 'time_ago(10) returns "10 seconds ago"');
+is(time_ago(30), '30 seconds ago', 'time_ago(30) returns "30 seconds ago"');
+is(time_ago(44), '44 seconds ago', 'time_ago(44) returns "44 seconds ago"');
+
+# Test minute boundaries
+is(time_ago(45), '1 minute ago', 'time_ago(45) returns "1 minute ago"');
+is(time_ago(60), '1 minute ago', 'time_ago(60) returns "1 minute ago"');
+is(time_ago(90), '1 minute ago', 'time_ago(90) returns "1 minute ago"');
+is(time_ago(119), '1 minute ago', 'time_ago(119) returns "1 minute ago"');
+is(time_ago(120), '2 minutes ago', 'time_ago(120) returns "2 minutes ago"');
+
+# Test hour boundaries - critical for the bug fix
+is(time_ago(60 * 44), '44 minutes ago', 'time_ago(44 minutes) returns "44 minutes ago"');
+is(time_ago(60 * 60), '1 hour ago', 'time_ago(60 minutes) returns "1 hour ago"');
+is(time_ago(60 * 90), '1 hour ago', 'time_ago(90 minutes) returns "1 hour ago"');
+is(time_ago(60 * 119), '1 hour ago', 'time_ago(119 minutes) returns "1 hour ago"');
+is(time_ago(60 * 120), '2 hours ago', 'time_ago(2 hours) returns "2 hours ago"');
+
+# Test day boundaries - this is where the bug was most visible
+is(time_ago(60 * 60 * 23), '23 hours ago', 'time_ago(23 hours) returns "23 hours ago"');
+is(time_ago(60 * 60 * 24), '1 day ago', 'time_ago(24 hours) returns "1 day ago"');
+is(time_ago(60 * 60 * 36), '1 day ago', 'time_ago(36 hours) returns "1 day ago"');
+is(time_ago(60 * 60 * 47), '1 day ago', 'time_ago(47 hours) returns "1 day ago"');
+is(time_ago(60 * 60 * 48), '2 days ago', 'time_ago(48 hours) returns "2 days ago"');
+is(time_ago(60 * 60 * 72), '3 days ago', 'time_ago(72 hours) returns "3 days ago"');
+
+# Test month boundaries
+is(time_ago(60 * 60 * 24 * 29), '29 days ago', 'time_ago(29 days) returns "29 days ago"');
+is(time_ago(60 * 60 * 24 * 30), '1 month ago', 'time_ago(30 days) returns "1 month ago"');
+is(time_ago(60 * 60 * 24 * 45), '1 month ago', 'time_ago(45 days) returns "1 month ago"');
+is(time_ago(60 * 60 * 24 * 59), '1 month ago', 'time_ago(59 days) returns "1 month ago"');
+is(time_ago(60 * 60 * 24 * 60), '2 months ago', 'time_ago(60 days) returns "2 months ago"');
+
+# Test year boundaries
+is(time_ago(60 * 60 * 24 * 365), '1 year ago', 'time_ago(365 days) returns "1 year ago"');
+is(time_ago(60 * 60 * 24 * 547), '1 year ago', 'time_ago(547 days) returns "1 year ago"');
+is(time_ago(60 * 60 * 24 * 731), '2 years ago', 'time_ago(731 days) returns "2 years ago"');
+
+# Test with DateTime object
+my $now = DateTime->now();
+my $past = $now->clone->subtract(hours => 25);
+is(time_ago($past), '1 day ago', 'time_ago(DateTime 25 hours ago) returns "1 day ago"');
+
+$past = $now->clone->subtract(days => 2);
+is(time_ago($past), '2 days ago', 'time_ago(DateTime 2 days ago) returns "2 days ago"');
+
+$past = $now->clone->subtract(months => 1);
+like(time_ago($past), qr/^(1 month|2[89]|3[01] days) ago$/, 'time_ago(DateTime 1 month ago) is reasonable');