diff --git a/changes/ticket28128 b/changes/ticket28128
new file mode 100644
index 0000000000..6d08c74242
--- /dev/null
+++ b/changes/ticket28128
@@ -0,0 +1,4 @@
+  o Documentation (hidden service manpage, sandbox):
+    - Document in the man page that changing ClientOnionAuthDir value or
+      adding a new file in the directory will not work at runtime upon sending
+      a HUP if Sandbox 1. Closes ticket 28128.
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index 019c8af757..097db065bb 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -611,6 +611,7 @@ GENERAL OPTIONS
     ServerDNSResolvConfFile
     Tor must remain in client or server mode (some changes to ClientOnly and
     ORPort are not allowed).
+    ClientOnionAuthDir and any files in it won't reload on HUP signal.
     (Default: 0)
 
 [[Socks4Proxy]] **Socks4Proxy** __host__[:__port__]::