diff --git a/build-constraints.yaml b/build-constraints.yaml
index 06cfba15..bd4bd03d 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3982,9 +3982,9 @@ packages:
         - autodocodec-yaml
         - cursor
         - cursor-brick
-        - cursor-fuzzy-time
+        - cursor-fuzzy-time < 0 # via fuzzy-time
         - cursor-gen
-        - fuzzy-time
+        - fuzzy-time < 0 # https://github.com/commercialhaskell/stackage/issues/6564
         - genvalidity
         - genvalidity-aeson
         - genvalidity-bytestring