diff --git a/build-constraints.yaml b/build-constraints.yaml
index 41cff539..ad3dcc11 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -7534,6 +7534,7 @@ expected-test-failures:
     - domain-optics # 0.1.0.2 https://github.com/commercialhaskell/stackage/pull/6102
     - flat # 0.4.4
     - flay # 0.4
+    - fmt # https://github.com/commercialhaskell/stackage/issues/6375
     - focuslist # 0.1.0.2
     - geojson # 4.0.2
     - heap # 1.0.4 https://github.com/pruvisto/heap/issues/11