diff --git a/build-constraints.yaml b/build-constraints.yaml
index 71ac9513..c9ab5308 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -7596,6 +7596,9 @@ expected-test-failures:
     - world-peace
     - xmlbf
 
+    # https://github.com/daanx/isocline/issues/1
+    - isocline
+
 # end of expected-test-failures