diff --git a/build-constraints.yaml b/build-constraints.yaml
index dd493b33..2b2fcf41 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4951,6 +4951,7 @@ expected-haddock-failures:
 skipped-haddocks:
 - approximate
 - invertible
+- modular # https://github.com/haskell/haddock/issues/900
 - sparkle # Java function failures tweag/sparkle#144
 # end of skipped-haddocks