diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index b117a23e461..befcd06d5ab 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -39,7 +39,7 @@
 == block_image.html 500x300_green.html
 != block_image.html noteq_500x300_white.html
 == object_element_a.html object_element_b.html
-== append_style_a.html append_style_b.html
+flaky_cpu == append_style_a.html append_style_b.html
 == height_compute_reset.html height_compute.html
 == width_nonreplaced_block_simple_a.html width_nonreplaced_block_simple_b.html
 == max_width_float_simple_a.html max_width_float_simple_b.html