diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7f8c5297..1f9c0df1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 Bug Fixes
 
+- Fixed a nasty bug where, while a mutator is blocked after calling `set_thread_blocked`, the collector may copy an object the mutator is using from the stack to the heap. In this case we need to ensure the object is not corrupted when it is copied and that we sync the object's fields back up once the mutator is unblocked. Currently this only affects `port` objects in the runtime.
 - Fixed a handful of small garbage collection bugs from the previous round of development.
 
 ## 0.9 - July 31, 2018