In my experience it is as Robert explained, shows up a lot when you turn on a device and it defaults to its previous state, so your turning on X devices, then changing the colour mode, then changing the hue, dim, saturation. for 5 devices thats 25 commands all at once.
The more devices or the bigger the group the more commands and the more likely it will fail.
The group app retries when the command fails, which works well enough for me, but it does mean the more ‘nested’ your groups. (a group of a group of a group) the bigger the delay.
