Best practices
Never use a leading forward slash
A leading forward slash is permitted in MQTT. For example, /myhome/groundfloor/livingroom . However, the leading forward slash introduces an unnecessary topic level with a zero character at the front. The zero does not provide any benefit and often leads to confusion.
– https://www.hivemq.com/blog/mqtt-essentials-part-5-mqtt-topics-best-practices/
“and often leads to confusion.”