diff --git a/build-constraints.yaml b/build-constraints.yaml
index 3ae5faff..6c984d72 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3618,6 +3618,7 @@ expected-test-failures:
     - graylog # 0.1.0.1 https://github.com/fpco/stackage/pull/1254
     - matplotlib # https://github.com/fpco/stackage/issues/2365
     - rematch # No issue tracker, sent e-mail to maintainer https://github.com/fpco/stackage/issues/376
+    - riak # https://github.com/riak-haskell-client/riak-haskell-client/issues/100
     - xlsior # https://github.com/rcallahan/xlsior/issues/1
 
     # Assertion failures, these can be real bugs or just limitations