Zigbee bulbs are notorious for being poor repeater devices, IMHO. Also, they are subject to be powering off by wall switches, or lamp switches, thereby causing the Zigbee mesh to have issues. The great thing about Sengled bulbs is that they are not Zigbee repeaters. Therefore, the mesh is never impacted if someone turns a bulb off via a physical power switch. I would encourage the use of a good smart outlet that is known to repeat signals well for your devices (i.e. the Xiaomi devices seem to be the most picky, since they are not Zigbee HA compliant devices.) I use Lowes Iris 3210-L outlets and have not had any issues with my zigbee mesh. Note, these outlets are known to not play well with Xiaomi devices.