diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2bf02f2841..f88d2c84a5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -603,6 +603,16 @@ static int add_one_ref_to_rev_list_arg(const char *refname,
 	return 0;
 }
 
+static int clear_commit_marks_from_one_ref(const char *refname,
+				      const unsigned char *sha1,
+				      int flags,
+				      void *cb_data)
+{
+	struct commit *commit = lookup_commit_reference_gently(sha1, 1);
+	if (commit)
+		clear_commit_marks(commit, -1);
+	return 0;
+}
 
 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 {
@@ -674,6 +684,9 @@ static void orphaned_commit_warning(struct commit *commit)
 		suggest_reattach(commit, &revs);
 	else
 		describe_detached_head("Previous HEAD position was", commit);
+
+	clear_commit_marks(commit, -1);
+	for_each_ref(clear_commit_marks_from_one_ref, NULL);
 }
 
 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index bfeb2a6512..569b27fe8d 100755
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -126,4 +126,17 @@ test_expect_success 'checkout does not warn leaving reachable commit' '
 	check_no_orphan_warning stderr
 '
 
+cat >expect <<'EOF'
+Your branch is behind 'master' by 1 commit, and can be fast-forwarded.
+EOF
+test_expect_success 'tracking count is accurate after orphan check' '
+	reset &&
+	git branch child master^ &&
+	git config branch.child.remote . &&
+	git config branch.child.merge refs/heads/master &&
+	git checkout child^ &&
+	git checkout child >stdout &&
+	test_cmp expect stdout
+'
+
 test_done