diff --git a/build-constraints.yaml b/build-constraints.yaml
index 30023be2..02ee4107 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -8097,6 +8097,7 @@ expected-test-failures:
     - openssl-streams # 1.2.3.0 asn1 encoding wrong tag
     - posix-paths
     - posix-pty # 0.2.2
+    - pkgtreediff # 0.6.0
     - prettyprinter
     - prettyprinter-ansi-terminal
     - rando # https://github.com/commercialhaskell/stackage/issues/4249