diff --git a/build-constraints.yaml b/build-constraints.yaml
index d9390fd3..25a53280 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -5041,6 +5041,9 @@ expected-test-failures:
     # https://github.com/commercialhaskell/stackage/issues/4294
     - asif
 
+    #
+    - mmark-ext
+
 # end of expected-test-failures
 
 # Benchmarks which are known not to build. Note that, currently we do not run