diff --git a/build-constraints.yaml b/build-constraints.yaml
index 0617acbd..28624186 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4059,9 +4059,9 @@ packages:
         - genvalidity-uuid
         - genvalidity-vector
         - mergeful
-        - mergeful-persistent
+        - mergeful-persistent < 0 # https://github.com/NorfairKing/mergeful/issues/4
         - mergeless
-        - mergeless-persistent
+        - mergeless-persistent < 0 # https://github.com/NorfairKing/mergeless/issues/3
         - pretty-relative-time
         - safe-coloured-text
         - safe-coloured-text-gen