Did we ever get a fix? I have finally got mine linked to HomeKit and it worked through the Home app for all of 5 mins before it changed to "this accessory is not responding". I added it to Tapo app afterwards so I could use it, and the bulb works fine through the Tapo app. 

  @Wayne-TP 

Just came back to write my solution. 

It has been stable for around 2 weeks without problems.  I have 3 access points including the router.  I don't have access to advanced settings in the router so the only thing I can do there is change the SSID name and turn off the wifi.  Nothing else is allowed, like choosing channels and wifi power.  My initial setup was 2.4 wifi only on my 2 tp-link plc access points. Both with the same SSID and everything on auto.  Bulbs stoped working after 3 days aprox.

My solution was to separate both access points.  Each one with its own SSID and fixed channels.  One on channel 1 and the other on 11. Encryption on TKIP and only 20 Mhz Channel width.  I manually chose the closest/strongest access point to each bulb.  After this everything is working perfectly.

  @CAGMEC thank you so much for your response. I don't know what most of this means so I'm afraid I'm going to have to try find someone to translate for me. I'm so annoyed that these are advertised and "plug and play" when they clearly aren't :( 

Wayne-TP wrote

If your Tapo L535 experiences frequent WiFi disconnection issues similar to the symptoms in this thread, check the following suggestions.

 

• Case One. Smart bulb managed by Tapo App.  
  • Check Case 1:  Cannot use the Tapo/Kasa app to control my smart device
  • What should I do if my Tapo smart devices keeps losing connection or going offline?
  • ​​​​If the light bulb cannot be controlled remotely with Tapo App, check suggestions under Case 2 in this article. Cannot use the Tapo/Kasa app to control my smart device

 

• Case Two. Smart bulb managed by a third-party Matter platform Apps.

Check the quality and signal strength of the router WiFi. Observe whether other devices on the same network experience the same WiFi disconnection phenomenon.

Suggestions in this article apply to this scenario as well. What should I do if my Tapo smart devices keeps losing connection or going offline?

 

 

If the problem remains, please share the following details when reporting the issue so we can offer more targeted suggestions.

1. What platform are you using to manage the Tapo L535? Tapo App or a third-party Matter platform app?

2. Model of your router. If you own a big network, please describe your network topology as clearly as possible. 

3. Detailed description of the problem you've encountered.

4. Troubleshooting steps you've tried. 

  @Wayne-TP 

This is absolutely not helpful.  The Tapo L535 has some problem with Wifi connectivity.  It either can't handle channel changes, multiple access points with the same SSID or changes in encryption type.  That is why after a few days if the wifi network changes channel, encryption or another access point has better coverage, it just stops responding.

I understand these are the first steps to correct problems, but there are firmware/hardware problems with the product.

Ill toss in my 2 cents. Now before anyone jumps on me because my lights are TAPPO L930-5 light strips I have to say the symptoms of random disconnects since the day I installed these are the same. These are HomeKit,, not matter but I wish they did matter. Still homeKit communication and matter are not much different on the main layer. 

Out of 160 smart devices I have owned these are useless when only one, or two, or none of the three turn on. Constantly interrupts automations to th point I no longer include them in any automations. 
HUB

Apple TV 4K (latest version with thread)

Apple TV 4K last version.

HomePod Mini

All latest software

WiFi 6 routers I have tried

GL.iNET Flint 2 (mediatech chipset) with stock firmware and latest stable OpenWRT firmware

Asus AC-RT86U with broadcom chipset

I have adjusted the wifi setting, the DHCP timing and release, gave them statick (reserved) IP addresses. 

I have tried so much that I dont have it in me to re-think everything over the last 5 month.

Ok, I'm done.

Thanks