Yes I did, but it's been a year and I don't remember what had to be done to fix it. About three months ago I replaced my Deco M9 Plus routers with another brand and so I can't even look at the Deco app anymore. (I still use all the TP-Link and Kasa Smart cameras, plugs, and switches though).

I'll post more if I can remember what it took to get the devices to add without the error.

  @Don.M If you can remember that would be great thanks.

I submitted a help request but no response yet.

Also asked for help on Reddit but no response either.

  @Tony Any chance you recall a fix for this issue?

Thank you!

@zooropean 

I have some saved email correspondence about the problem. I was contacted by Eva Liu from TP-Link, and after giving her some logs she spoke with other TP-Link engineers. They suggested a beta firmware, which she sent me a link to. That fixed the problem for me. The firmware was created to fix a similar issue with Philips Hue lights, and they thought (correctly) that it would fix the HS300 issue.

  @Don.M  if you happen to still have the link please let me know.

Thank you!

Please use this at your own risk, I don't know whether it matches your hardware, or will fix your problem or not.

Best of luck

https://static.tp-link.com/2020/202012/20201225/Deco_M9Plus_v2_fail_to_add_Philip_hue_bridge_when_works_in_AP_mode.zip