Fix
Remove switch from zigbee group. Add binding on both endpoint 1 and 2 of inovelli switch to the group.
More Information
I had a discussion on the zigbee2mqtt discord channel.
Basically the current way of handle binding/groups should not be used. Apparently actor device/receiving devices shouldn’t be in the same group, even if they are separate end points.
The correct way to handle it is to have both endpoints bound to the group, but neither be in the group. That seemed to handle it correctly in my testing and the led bar showed the correct % lit corresponding to the brightness of the group.
This documentation linked above should be updated and possibly firmware changed to handle it better
I closed the issue I had on github as this does not seem to be a zigbee2mqtt issue but on the Inovelli side.