So I have a fair amount of Zigbee devices. They generally all work well, although my Ledvance RGBW bulbs still like to ignore commands from time to time. Lately, though, I’ve noticed that after adding a new device to the mesh, after a period of time, some other device stops responding to commands, and no longer shows up in the neighbor or child tables at all. I can usually get it back by power cycling it a few times. It seems that when the mesh reconfigures to accommodate the new device, a previous device loses its path to the HE.
Is there any way to prevent this or make the HE go and search for the missing device?
Possible you need more repeaters. I think the max per repeater is 32 theoretically but in practice I assume it's much less. I usually maintain at least one powered device for every 6. Most of the time much more than this but there are a few areas of the house which have a lot of battery powered devices.
Many Zigbee bulbs are poor repeaters for non-bulb devices. I'm not sure if anyone has documented these as being one, but it's a caution that's worth looking into for any Zigbee bulb (except Sengled, which are known not to repeat and thus avoid this problem; it's possible newer bulbs, including many Zigbee 3.0 models, are better at this--but the Zigbee profile or age of the device is no guarantee either way). For this reason, some people recommend keeping Zigbee bulbs on a separate network. A second Hubitat is one option; a Hue Bridge (if your bulbs are not ZHA bulbs), plus the Hubitat integration, is another.
The hub has a limit of 32 directly-connected Zigbee "end devices." This means devices that do not repeat and connect directly to the hub. Repeaters allow you to extend this number more or less indefinitely, but each repeater also has its own limit, often far less (something like 4-8 might be a good estimate, perhaps more for more powerful devices--but, of course, there is no gurantee that a device will use a repeater just because it exists). Most Zigbee bulbs are repeaters, but see again the caution above.
My guess is that one or both of these issues might be causing your problems. Assuming you have enough other repeaters, you could test this theory by un-powering the bulbs during the pairing of a new device to see if it helps, but keep in mind that Zigbee devices can freely re-route, so this isn't a viable long-term solution. If the bulbs themselves are having problems, too, that's a bit more odd (unless they are, in fact, end devices too)
All of my devices are mains-powered, and it’s my understanding that the Lightify Bulbs can serve as repeaters, although looking at my route table, it’s interesting to note that none of them currently are doing so. Every device connected via another node is routing through either a Jasco switch or Lightify plug.
The issue with the bulbs that I’m having pertains to some misbehavior when they’re in groups that I’m trying to track down as either an issue with the driver or the groups app. I don’t have enough data to build an issue report out of there yet, but I don’t think that ties into this routing mishap. When my grouped bulbs get cranky they still show up in the route table and usually cooperate with commands not involving the group. In this case, the route table is straight up missing a device.
Please realize that they are terrible routers. And, all the table shows is that they aren't functioning as primary routers that are one hop away from the hub. They could very well be functioning as routers two hops away from the hub, dropping devices from their routing table. A long-standing recommendation here has been to keep ZLL zigbee bulbs that repeat on the Hue hub, and ZHA bulbs that repeat on a separate Hubitat hub,
I don’t have any issues with these since replacing all of the A-19 rgbws with Hue (on the Hue bridge) leaving only 18 Ledvance recessed rgbws, 5 Ledvance flex xl strips, 2 Ledvance garden spots, 2 Sengled color bulbs, 6 GE Zigbee dimmers, and 2 Sonoff plugs on that HE’s Zigbee mesh. I know that overheating was an issue with some of the bulbs and Ledvance replaced almost all of my A-19s over the course of a couple years due to them burning out. The first symptom was usually that their Zigbee radio would stop responding and they wouldn’t turn off, then anything routing through them would have issues. I saw much better reliability with the remaining lights once the bulbs were gone. Even though everything technically worked properly, everything is instant now, so dividing your mesh in half may be a solution.
