Ok, the past week I’ve been experiencing this issue. I think I know a little bit more on what is happening and what is not happening. And perhaps I even have part of the solution. (I’ll try to keep it short)
After my Homey Pro got updated to 12.13.0-rc.3, I noticed that all the Zigbee was slow to respond. My Zigbee network is a mix of both (mostly Tuya based) smart plugs and (mostly IKEA based) smart bulbs. In addition I have some Eglo lights, a Robb shop smart dimmer and that’s about all the Zigbee I have.
So, the issue was noticeable because lights were not switching on as expected. I wasn’t sure where the issue was and what caused it, so I started this topic. After concluding that it was in the Zigbee part I searched the community and found more people with Zigbee issues since 12.13.0-rc.3.
For another issue I was in contact with Athom customer support and raised this issue there as well. There it was mentioned that my Zigbee devices did not start behaving different because of the firmware update although this is the moment on which it became noticeable. He will check with some colleagues to be on the safe side.
In 12.13.0-rc.5 the cleanup of unknown nodes has been improved and I can confirm that.
I haven’t checked the Zigbee interface in the Homey Developer Tools for a while, but now I did and I noticed that especially the Tuya Zigbee devices that I have are generating a sh$t load of messages! About every second I see a new TX. When I divided the number of messages by 3600 I got to around 11 hours and that was the moment on which the most recent RC was installed.
Perhaps this has always been the case, but I am pretty sure I only notice this as of the installation of 12.13.0-rc.3.
So, I tried cutting down the communication by limiting the polling frequency of the smart plugs from every 60 seconds to every hour. This didn’t solve the issue. I involved Google Gemini and it turned out I was limiting how often Homey pulls the data from the smart plug. For some reason the smart plug was sending the data to the Homey way more often than that. Perhaps this was always the case, but due to the updated interface Homey also actually starts processing this.
So, again together with Gemini, I updated my own version of the Tuya Zigbee app and added a setting to the smart plugs where you can indicate how much Volt, Ampère or Watt either 3 of these need to change before sending a message to Homey.
Somewhat at the same time my Homey Pro got updated to 12.13.0-rc.6 and as of the past days things seem to be better. I am not sure if it is the changes I made to the app, the 12.13.0-rc.6 or a combination of the two.
You can move Tuya smart plugs to a separate Smartthings, Tuya or other Zigbee hub and integrate it that way, but as far as I can see the smart plugs will continue to send this many messages and clog the 2.4Ghz network. The only thing seems to be to push this setting to the Tuya smart plugs. I still need to update the app for some of the smart plugs that seem to be a little bit different. After installing the app you will HAVE to change a setting and hit save, because the new settings will only be applied after changing and pushing one setting.
I am happy to share this version of the app. Just need to know how I can do that best.
Edit: Checking if the change has effect is a rather tedious job. You’ll have to refresh the Homey Developer Tools Zigbee page, sort descending by # TX, check if # TX increased a lot more than expected. And in my case this is for 28 devices!
Edit 2: After updating the app I do for example see the change for this type:
But not for this one:
Which is weird because in the files where I made the changes I do see this:
“zigbee”: {
“manufacturerName”: [
“_TZ3000_3ooaz3ng”,
“_TYZB01_iuepbmpv”,
“_TZ3000_g5xawfcq”,
“_TZ3000_gjnozsaz”,
And I do see:
“productId”: [
“TS0121”,
“TSO121”,
“TS011F”
Edit 3: thanks to Gemini again: these are Tuya based, but if I connect them to the Nous app rather than the Tuya Zigbee app, I can update the Tuya Zigbee app as much as I want…. I will never get these added settings 
