Okay, I know someone is going to say ‘just bind them’ or whatever… But I can create a group in Home Assistant, and if I tap a button to turn off a group of light bulbs and 1 bulb stays on WTH does Home Assistant not see that and try to turn it off again?
This seems like a common thing in Zigbee devices, but it may happen elsewhere. Can Home Assistant not handle this?
I have the same issues w/ some Ikea shades. When triggering the HA group sometimes a shade won’t actually open or close.
Do you think it is just a zigbee issue?
Have the same problem, but my group is created in zigbee2mqtt.
Was thinking about creating a group in HA instead, but maybe not much use then? 
See:
Also relevant: Make sending Zigbee commands more resiliant by tonyroberts · Pull Request #76939 · home-assistant/core · GitHub
also relevant: ZHA Zigbee lights don't switch on/off reliably when triggered as part of a group or scene · Issue #76938 · home-assistant/core · GitHub
Yep, I also migrated from a Conbee 2 to a Sonoff ZigBee stick but it still happens once in a while (though with MUCH less frequency).
Same issue here, any advice?
ZigBee light groups receive commands through multicast. There’s no way to know the order in which they are received. It isn’t that simple to add retries.
If you’re having issues with zigbee light groups there’s likely a network/coordinator/device issue. As that already is more efficient that sending commands to each bulb 1 by 1.
Same here with ZHA. I decided to install 6 zigbee smart bulbs instead of a single smart switch and although all 6 bulbs are in the same zigbee group, occasionally 1 doesn’t respond to the multicast. It’s not always the same bulb either.
I find it’s more likely to play up after I’ve added new zigbee devices, such as switches, to the network as well.
I have a zigbee group which works perfectly but when i try to control the lights seperately one of them wont react to anything.