diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bf8c11d66583e8bf93a77c61ad7f3acb2677f38..82bbf7a704bdf303d70e262b7a54bbf5aba20d9f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -142,6 +142,8 @@ HeapLang, which is now in a separate package `coq-iris-heap-lang`.
 * `wp_strong_adequacy` now applies to an initial state with multiple
   threads instead of only a single thread. The derived adequacy lemmas
   are unchanged.
+* `pure_exec_fill` is no longer registered as an instance for `PureExec`, to
+  avoid TC search attempting to apply this instance all the time.
 
 **Changes in `heap_lang`:**