diff --git a/build-constraints.yaml b/build-constraints.yaml
index f493775f..2f492124 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -37,7 +37,7 @@ packages:
         - interpolatedstring-qq2
         - prospect
         - do-notation
-        - unagi-chan
+        - unagi-chan < 0.4.1.1 # #4765
         - type-errors
         - loopbreaker