Disable decrypt_polling by default + add comment (#3244)

config/config.example.yml

@@ -352,10 +352,13 @@ feed_threads: 1
 ## Note: This part of the code generate a small amount of data every minute.
 ## This may not be desired if you have bandwidth limits set by your ISP.
 ##
-## Accepted values: true, false
-## Default: true
+## Note 2: This part of the code is currently broken, so changing
+## this setting has no impact.
 ##
-#decrypt_polling: true
+## Accepted values: true, false
+## Default: false
+##
+#decrypt_polling: false
 
 
 # -----------------------------