diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index ac4ee8c5..42029680 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -7690,7 +7690,7 @@ sub main {
             );
 
             # Check each slave for checksum diffs.
-            my $max_diffs = 0;
+            my %diff_chunks;
             foreach my $slave ( @$slaves ) {
                eval {
                   my $diffs = $rc->find_replication_differences(
@@ -7700,10 +7700,9 @@ sub main {
                   );
                   PTDEBUG && _d(scalar @$diffs, 'checksum diffs on',
                      $slave->name());
-                  if ( my $n_diffs = scalar @$diffs ) {
-                     # https://bugs.launchpad.net/percona-toolkit/+bug/1030031
-                     $max_diffs = $n_diffs if $n_diffs > $max_diffs;
-                  }
+                  # Save unique chunks that differ.
+                  # https://bugs.launchpad.net/percona-toolkit/+bug/1030031
+                  map { $diff_chunks{ $_->{chunk} }++ } @$diffs;
                };
                if ($EVAL_ERROR) {
                   if ( $o->get('quiet') < 2 ) {
@@ -7716,7 +7715,7 @@ sub main {
                   $tbl->{checksum_results}->{errors}++;
                }
             }
-            $tbl->{checksum_results}->{diffs} = $max_diffs;
+            $tbl->{checksum_results}->{diffs} = scalar keys %diff_chunks;
          }
 
          # Print table's checksum results if we're not being quiet,
diff --git a/t/pt-table-checksum/bugs.t b/t/pt-table-checksum/bugs.t
index e0149c9a..8c6e0fe7 100644
--- a/t/pt-table-checksum/bugs.t
+++ b/t/pt-table-checksum/bugs.t
@@ -42,7 +42,7 @@ elsif ( !$slave2_dbh ) {
    plan skip_all => 'Cannot connect to sandbox slave2';
 }
 else {
-   plan tests => 9;
+   plan tests => 10;
 }
 
 # The sandbox servers run with lock_wait_timeout=3 and it's not dynamic
@@ -155,7 +155,6 @@ $slave1_dbh->do("SET SQL_LOG_BIN=1");
 
 $output = output(
    sub { pt_table_checksum::main(@args, qw(-t test.t --chunk-size 10)) },
-   stderr => 1,
 );
 
 is(
@@ -164,6 +163,21 @@ is(
    "Bug 1030031 (wrong DIFFS): 2 diffs"
 );
 
+# Restore slave2, but then give it 1 diff that's not the same chunk#
+# as slave1, so there's 3 unique chunk that differ.
+$slave2_dbh->do("UPDATE test.t SET c='e' WHERE id=5");
+$slave2_dbh->do("UPDATE test.t SET c='' WHERE id=26");
+
+$output = output(
+   sub { pt_table_checksum::main(@args, qw(-t test.t --chunk-size 10)) },
+);
+
+is(
+   PerconaTest::count_checksum_results($output, 'diffs'),
+   3,
+   "Bug 1030031 (wrong DIFFS): 3 diffs"
+);
+
 # #############################################################################
 # Done.
 # #############################################################################