I am relatively new to Home Assistant but don’t think the problem is with HA. I have zigbee light switches that use automation to trigger a scene. The vast majority of the time not all the lights in the scene do what they should. For example I have six GU10 bulbs and have a scene where they are all set to white, and then another where they are all off. I use the light switch to trigger the relevant scene. But iften when I turn on the light switch not all six lights turn on. If I switch them off and back on they will often then all work. The same happens when I switch them off. Sometimes ut takes a few goes. Sometimes the switch doesn’t switch them all off and I have to use HA to switch off the lights individually.
If you are using Home Assistant’s scene, it sends a separate command to each one of your six GU10 lights. That’s six separate commands transmitted consecutively. If they are all Zigbee-based, your Zigbee network appears to be occasionally dropping one or two commands (so some lights never receive the command to turn on/off).
A more efficient method is to create a Zigbee group, containing all six Zigbee lights, and have Home Assistant control the Zigbee group. In this situation, only one command is transmitted and all six receive it simultaneously.
How to create a Zigbee group depends on which Zigbee integration you are using (ZHA or Zigbee2MQTT).
If the six lights are not all Zigbee-based, and whatever integration they use doesn’t support native grouping, then there’s not much that can be done to improve performance.
I have build a zigbee group using ZHA. My process was then to create a scene called “lights off” for example. The idea was to then create an automation so when the light switch is in the off position it triggers that scene. This all works well except when I add the zigbee group (entity) to the scene, it adds other zigbee groups automatically and I cant find a way to get rid of them. This means the one switch does something to the other groups.