Zigbee unstable since 2.6.3(?)

[kambyte0]

What happened?

I'm hesitant to report this issue, but I'm genuinely stuck and need help understanding what caused my previously stable Zigbee network to become unreliable.

I'm running the latest Home Assistant OS, and recently upgraded Z2M from 2.6.2 to 2.6.3 and updated my SLZB-06 coordinator firmware from 20240710 to 20250325, all within the same day. Since these updates, I'm experiencing widespread device instability.

My Tuya PIR sensors are showing odd behavior - their LEDs blink on motion detection, but the status no longer updates in Z2M. Re-pairing temporarily fixes the issue, but it recurs within days. My IKEA Parasoll devices keep dropping from the network, and Aqara devices are becoming unavailable as well.

I know what you might be thinking - that these devices are known for stability issues. However, this exact setup has been rock solid for 2 years with these same devices, so I don't believe this is an inherent device compatibility issue.

I've tried several troubleshooting steps: downgrading the firmware back to 20240710 (no improvement), switching to Zigbee channel 25 and re-pairing all battery devices (stable for about a day, then issues returned), and multiple device deletions and re-additions (no lasting improvement).

Some additional details: no new devices have been added since the issues began, battery levels are adequate, Z2M logs show no errors, and the network map shows affected devices as disconnected from routers (though some still report values intermittently). Interestingly, only end devices are affected while routers remain stable. Router coverage is good across all floors with multiple routers per floor.

Any guidance would be greatly appreciated. I'm really thinking that there might be an issue with 2.6.3?

What did you expect to happen?

Stable setup, no dropping sensors.

How to reproduce it (minimal and precise)

Unfortunately, no idea.

Zigbee2MQTT version

2.6.3

Adapter firmware version

ZStack3x0 / 20240710

Adapter

SLZB-06 (CC2652P)

Setup

Mini PC, proxmox, haos, Z2M over the add-on store.

Device database.db entry

No response

Debug log

no error in the log

Notes

No response

[tjkgdd]

Yes, I'm having a similar problem too.

For some time now, after upgrading Zigbee2MQTT to version 2.6.3 or updating my SLZB-06, my Zigbee network has also been very unstable. It can restart once or twice a day, Zigbee2MQTT disconnects from the SLZB controller, and some devices lose connection. I either have to reset them or, in the case of mains-powered devices, unplug and plug them back in

zslb L core: v2.9.8 / zigbee: 20250325

Just downgraded from 3.1.3 to see if that problem persists on older version of slzb.

[JC38]

I’m also having an issue with version 2.6.3.
From the drawings below, we can see that CPU and network traffic increased. This started after upgrading from version 2.6.2 to 2.6.3.
When I review the logs, it appears that many messages are repeated.
The main consequence is a large number of timeouts or the HA scripts not running as expected. For example, lights switch on many seconds after a presence detector has detected someone.

Would it also be possible to have, in the interface, a counter of the messages published over a given period of time, the aim being to see if one or more devices are spamming the network?

[mariusgoldberg]

Hi, I am experiencing the same issues as described above on 2.6.3. Not sure what the cause is but network gets unresponsive within minutes. I can still access and use zigbee2mqtt webinterface without obvious issues but all commands send to devices are receiving timeouts. Once I restart zigbee2mqtt from the webinterface everything works normal for a period of time until it breaks again. Also seeing duplicate messages in log.

However, since I also moved to a new flat with my setup and in that instance added quite a number of new devices / position of devices changed in relation to one another, I am not sure it was the update to 2.6.3 (which I updated to in the new flat) causing the issues or wether the network is unstable due to not completed re-setup of devices / introduction of new devices. But the issues described above are the same.

I will try to downgrade to 2.6.2 and see if that changes anything.

[vjenne]

Yes, same problem here. I just can't get my network to keep running for more than 24 hours. In the loggin I suddenly start to get a lot of errors from several devices, than complete chaos in the logging with repeating messages. After this I cant control my devices anymore. SLZB still report that 1 client is connected to the socket(i suppose this is zigbee2mqtt) but I think the communication between z2m en slzb is broken by then.

I had an slzb 06. I thought it was beacuase of this one going faulty so I bought an SLZB MR4U. But I have exactly the same issues. Already did a complete rejoin of my network and switched from channel 26 to 20.
Since I always thought it was beacause of the zigbee network itself I didn't try to downgrade to z2m 2.6.2, so thats what I'm trying to do this evening...

[kambyte0]

I think we're going to mix various issues into the same thread.

For transparency: Initially I stated that I have a slzb 06m - however, its an slzb 06 (CC2652P) like many others here. Maybe there's a mismatch between FW / 2.6.3, I dont have any other explanation. Sidenote: The devices (the ones which are stable) are reacting pretty fast. No issues at all at the complete netword. I'm also more on the country side so I can exclude issues from others in the area. It has to be something around z2m / FW. I'm open to share any other information and doing further tests. However, not sure how as the devices are just dropping without any error somewhere.

[JC38]

Here is the fw info for my SLZB-06.
Just to compare with those having the same issues withe the same hardware

[alkandery75]

Same issue for me, it's nightmare :

• Zigbee2MQTT Mesh is very slow
• Automations stopped working
• Motion Sensors stopped working
• IKEA Battery powered smart switches stopped working
• Some Moes light switches starts disappearing from the setup
• Some IKEA Bulbs starts disappearing from the setup
• Permit Join is useless and doing nothing
• Can't add any new device to the setup

This is unbelievable, same issues with last month update as well, and system was unstable for more than 2 weeks. I'm start thinking to move away from Zigbee2MQTT and go for WiFi or Matter since Zigbee2MQTT is totally unstable and very noisy.

How to reproduce it (minimal and precise)
Enable "Permit join (all)" and push the pairing button on Tretakt: nothing happens

Zigbee2MQTT version
2.6.3-1

Adapter
SMLIGHT SLZB-06

Setup
Home assistant Yellow

[JC38]

So, could we say that people using SMLIGHT SLZB-06 are getting this problem ? Nobody else with a different controller but with a CC2652P chipset ?

[Tomcat86878]

I am having the same issue as well. Using Slaesh CC2652RB USB Stick with newest Z-Stack firmware (march 2025).

[lovwyr]

My System shows more or less the same behavior, but with an sonoff_zigbee_3.0_usb_dongle_plus.

[tjkgdd]

On November 24th, I downgraded zigbe2mqtt to version 2.6.2.1.

SLZB-06 downgraded ZigBee firmware to version 20240710.

I left SLZB OS at 3.1.3.

Everything works for now. Maybe it's a coincidence or luck. ;-)

[alkandery75]

On November 24th, I downgraded zigbe2mqtt to version 2.6.2.1.

SLZB-06 downgraded ZigBee firmware to version 20240710.

I left SLZB OS at 3.1.3.

Everything works for now. Maybe it's a coincidence or luck. ;-)

I'll try this and check out.

[JC38]

Rollback to 2.6.2.1 done a few minutes ago. At the first sight, reactivity is back again and huge latency disappeared.

[alkandery75]

Rollback to 2.6.2.1 done a few minutes ago. At the first sight, reactivity is back again and huge latency disappeared.

How to rollback if I didn't backup ?