Light group not working

[lociii]

Key	Value
host_os	HassOS 4.11
installation_type	Home Assistant OS
os_name	Linux
os_version	4.19.127-v7l
python_version	3.7.7
supervisor	229
version	0.112.4

zigpy-znp installed from source
git+https://github.com/zha-ng/zigpy-znp.git@dev#zigpy-znp==1.0.0

Running on a TI CC2531

After creating a group and restarting HA, the following pops up in the log

2020-07-21 14:54:17 ERROR (MainThread) [homeassistant.util.logging] Exception in functools.partial(<function async_add_entities at 0xb22ec9c0>, <bound method EntityPlatform._async_schedule_add_entities of <homeassistant.helpers.entity_platform.EntityPlatform object at 0xa8321710>>, [(<class 'homeassistant.components.zha.light.Light'>, ('68:0a:e2:ff:fe:b7:b6:97-1', <homeassistant.components.zha.core.device.ZHADevice object at 0xa83b68d0>, [<homeassistant.components.zha.core.channels.general.OnOffChannel object at 0xa83b6c70>, <homeassistant.components.zha.core.channels.general.LevelControlChannel object at 0xa83b6ad0>, <homeassistant.components.zha.core.channels.lighting.ColorChannel object at 0xa83b6cb0>])), (<class 'homeassistant.components.zha.light.Light'>, ('58:8e:81:ff:fe:21:88:6b-1', <homeassistant.components.zha.core.device.ZHADevice object at 0xa83b6e10>, [<homeassistant.components.zha.core.channels.general.OnOffChannel object at 0xa83e2e90>, <homeassistant.components.zha.core.channels.general.LevelControlChannel object at 0xa83e2dd0>, <homeassistant.components.zha.core.channels.lighting.ColorChannel object at 0xa83c6070>])), (<class 'homeassistant.components.zha.light.LightGroup'>, (['light.left', 'light.right'], 'light_zha_group_0x0002', 0x0002, None))]) when dispatching 'zha_add_new_entities': ()
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/zha/core/discovery.py", line 46, in async_add_entities
    to_add = [ent_cls(*args) for ent_cls, args in entities]
  File "/usr/src/homeassistant/homeassistant/components/zha/core/discovery.py", line 46, in <listcomp>
    to_add = [ent_cls(*args) for ent_cls, args in entities]
  File "/usr/src/homeassistant/homeassistant/components/zha/light.py", line 491, in __init__
    super().__init__(entity_ids, unique_id, group_id, zha_device, **kwargs)
  File "/usr/src/homeassistant/homeassistant/components/zha/light.py", line 105, in __init__
    super().__init__(*args, **kwargs)
  File "/usr/src/homeassistant/homeassistant/components/zha/entity.py", line 220, in __init__
    f"{zha_device.gateway.groups.get(group_id).name}_zha_group_0x{group_id:04x}"
AttributeError: 'NoneType' object has no attribute 'gateway'

[puddly]

Thanks for the bug report, it's now fixed in the latest dev commit. I have confirmed that multi-device light groups re-appear without issue after a restart using that specific version of Python and HA.