diff --git a/build-constraints.yaml b/build-constraints.yaml
index d1fc30d0..a9b6804b 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3180,6 +3180,9 @@ expected-haddock-failures:
 
     # https://github.com/iand675/metrics/issues/5
     - metrics
+
+    # https://github.com/camfort/fortran-src/issues/29
+    - fortran-src
 # end of expected-haddock-failures