diff --git a/CHANGES/4013.bugfix b/CHANGES/4013.bugfix
new file mode 100644
index 00000000000..1793f2137b5
--- /dev/null
+++ b/CHANGES/4013.bugfix
@@ -0,0 +1 @@
+Fixed race conditions in _resolve_host caching and throttling when tracing is enabled.
diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index 21451c9ff83..f48891e83c9 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -132,6 +132,7 @@ Jian Zeng
 Jinkyu Yi
 Joel Watts
 Jon Nabozny
+Jonas Obrist
 Joongi Kim
 Josep Cugat
 Joshu Coats