diff --git a/docs/ftldns/configfile.md b/docs/ftldns/configfile.md
index 81b2685..75eee83 100644
--- a/docs/ftldns/configfile.md
+++ b/docs/ftldns/configfile.md
@@ -1,5 +1,7 @@
 You can create a file `/etc/pihole/pihole-FTL.conf` that will be read by *FTL*DNS on startup.
 
+Note: comments need to start with `#;` to avoid issues with PHP and `bash` reading this file. (See [https://github.com/pi-hole/pi-hole/pull/4081](https://github.com/pi-hole/pi-hole/pull/4081)  for more details)
+
 Possible settings (**the option shown first is the default**):
 
 ---