SONOFF SNZB-04PR2 does not transmit the first change after a long period of standby

[H4usi]

Hi,
I bought the new SonOff SNZB-04PR2 and installed four of them. The first test run went very well. The latency was incredibly fast, especially with frequent changes.

My problem, however, is the opposite, when not much is happening. It seems that if I don’t use the window for a few hours, the first change isn’t transmitted. If I then close the window again and open it, every change is transmitted immediately and very reliably. It only ever affects the first change after a few hours.

There is a router right next to the sensor. And technically, the coordinator is positioned so that it can be addressed directly. I have 51 Zigbee devices in my network, and these are the only ones exhibiting this kind of behavior.

Does anyone else have these sensors and a similar problem?

I’m using:

• HomeAssistant: 2026.4.1
• Zigbee2MQTT: 2.9.2-1
• Coordinator: Sonoff ZBDongle-P
• Firmware SonOff SNZB-04PR2: 1.0.1 (20251029)

[andrei-lazarov]

The issue might go away with a reset of the sensor. Here are some general tips you could apply.

Improve your network and try pairing again:

• Update coordinator firmware
  (Use a modern and well-supported coordinator)
• Pair directly through the coordinator (or try other devices, use drop-down on Permit join)
• Power-off 'bad' routers (e.g. Telink Tuya, AwoX)
• Add USB 2.0 extension cable to dongle coordinators
• Change Zigbee channel (find the one with least interference; if possible, stick to the defaults: 11, 15, 20, 25)

It may also help to restart Z2M between pairing attempts

[koichirose]

Hello, I have the same issue. Did you ever fix it? A reset did not help.
Using Z2M 2.9.2, Sonoff ZBDongle-E. Sensor is a bit far away from the coordinator, but I have no issues with all my other 40 devices and some of them are even further away (and battery powered as well).

[H4usi]

I did what I do best: nothing. After two or three days, the problem had sorted itself out. Or rather, I haven’t noticed it again since. It’s quite stable now.

I wish I knew what caused it.

[koichirose]

Hmm I can report the same: no issues here for the past few days even after not touching the doors for hours. Weird.

[erugeri]

So far it's working for a few days here too, how could this be possible ?

[koichirose]

Nevermind, it failed to update the status again here.

[erugeri]

Also here today :(

[erugeri]

Same issue with Z2M 2.9.2 and Sonoff Dongle-Max V1.0.7 Stable as coordinator, many Sonoff S60ZB and Sonoff Mini-R2 as routers in the network on last firmware available. 1.0.1 for detector as well.
I see the device triggers the red light so the change is detected but no message on MQTT. It happens usually once every 10 or 20 change.
Already tested to remove completely the device and re-add it.
Thanks for your help.

[erugeri]

Fyi, previously I was using ewelink app without Z2M and their web service for real time and the devices were working perfectly like that.
So I think the hardware is not the cause here.

[erugeri]

I just bought 2 SNZB-04P (not PR2), hopefully they will work better with Z2M. I'll let you know.

[erugeri]

Just installed the SNZB-04P, so far I don't see any issue with these devices (and I still see some with the -R2).
I'll keep you posted if it happens (I have both devices on two garage doors to detect discrepancies printing with error logs)

[erugeri]

SNZB-04P work perfectly while SNZB-04PR2 still regularly don't report change. I'm glad I found a working solution.
-O4PR2 are a bit cheaper, bigger but allow AA batteries while P are CR2450 which is more specific.
Anyway if someone is looking for a realiable solution...

[erugeri]

I don't know of it's useful or if it could be the origin of the issue but I see the following log multiple times :

May 06 00:10:02 rpi pnpm[1175]: [2026-05-06 00:10:02] error: z2m: No converter available for 'state' on 'snzb04pr2-garage-tesla': ("")

[andrei-lazarov]

cc @CubeZ2mDeveloper

[CubeZ2mDeveloper]

Hi,

Thanks for the feedback.

We have received the reports about the SNZB-04PR2 sometimes not transmitting the first state change after a long standby period. We will arrange an investigation on our side and try to reproduce this behavior.

Sorry for the inconvenience, and thanks again for your feedback.

[H4usi]

I don't think this has anything to do with Zigbee. I think the devices are just defective. I've installed four of them, and two of them have an extremely sensitive sensor.

They trigger multiple times when opening and closing the window, sometimes even with a movement of just a few millimeters.

I think I'll contact Sonoff directly about this.

Here’s a Video, sorry for the poor quality; it was late at night. https://github.com/user-attachments/assets/a5c6faaf-d4d6-42ae-bb02-547609fcd315