Wow, I’m sorry you’re dealing with all of that!
There’s definitely been something weird going on with zigbee on the smartthings platform over the last few months, although I don’t think anyone’s been able to pin it down. Lots of concerns about devices being marked unavailable And devices, including the smartthings branded ones, dropping off the network frequently.
Because smartthings is a cloud – based multiprotocol platform which allows for literally dozens of different device configurations, it can be really difficult to tell exactly what’s going on.
So I wish I had a simple answer, but I don’t. The firmware update definitely seems like a candidate, but there were also some platform updates around the same time, so who knows?
This is absolutely the thing I hate worst about any platform, but particularly this one: when things that worked on Monday just stop working on Tuesday without the end-user haven’t changed anything.
One other thought: zigbee bulbs as a potential problem
One other question we haven’t asked yet: do you have any zigbee bulbs, any brand, connected directly to the smartthings hub? I ask that because most of the brands have proven to be unreliable repeaters. They can get a kind of “buffer overflow” condition where they will drop messages, which can make it look like a sensor is having problems when in fact the sensor is fine and it’s that the bulb isn’t passing its messages along. (Devices connected to a hue bridge don’t have this issue, just ones connected directly to the smartthings hub.)
This is a known issue, confirmed by SmartThings staff, but nobody has a fixed yet other then some tricks to keep the sensors from using the bulbs as repeaters. And those tricks can get overridden in situations like the one you mentioned where it’s the hub itself that goes off-line for a while.
That may not have anything to do with the issues you’re saying, but I just wanted to mention it as it does create similar issues.
Back to your specific issue…
The only other thing I can think of at this point is to start a new thread with the sensor brand and model in the title that says they keep dropping off line and see if anybody has found any tricks specific to that device. I don’t have any of those and I haven’t really looked at them. You never know: somebody in the community may have some suggestions.
Zwave as an alternative?
I don’t know if this helps any, but you’re not the only person in the last four months or so who said they’ve switched over to Z wave to improve reliability In a SmartThings context.
I do feel confident that it’s not the zigbee protocol itself: there are lots of other systems, including ones at hospitals and utility companies, based on zigbee which run really well. And for that matter the Phillips hue zigbee system doesn’t seem to have any of these issues even when it’s in the same house. So I do feel a little protective of the protocol in that sense, I hate to see “zigbee” get a bad name because of a specific platform implementation.
At the same time, I believe the people absolutely when they say their zwave devices are working more reliably in this context. (on the other hand, there are some people in the same timeframe who have had all their Z wave devices stop working, but there do seem to be fewer of those.)
Again, I just wish I had a better answer. So I know it doesn’t help any, but I do feel your pain.