RMerlin was spot on [as usual] with his response to my original post ... problem was coming from Trend Micro code [closed source].
I have perfectly stable RT-AX86U's on 386.1 - HOWEVER ... in my view after flashing 386.1 firmware [with USB ejected] it is ESSENTIAL to do a full WPS button factory reset if you want proper stability. Even with that - my AX86U still does NOT like Guest WiFi 1 being used at all - whether across AiMesh nodes or confined to the Aimesh main Router ["buggy" errors abound] and I do NOT enable AiProtection - but prefer to rely on Skynet addon.
If you have ever enabled AiProtection and then later disable it - the problem remains - you must go to the "Administration" Tab and then to "Privacy" sub-tab and hit "Withdraw" button on the section denoting AiProtect / QOS etc.
Sadly - that blows out the use of FlexQOS, my favourite QOS add-on ... so I have had to revert to cake-qos for decent buffer bloat reduction.
Actually i removed my ovpn client and turned off my YazFi 2,4Ghz guest network and then i removed the guest network.
I went into YazFi config with vi and set everything to default again and saved, rebooted, let it run with just my isp for some hours, without any guest wifi and most errors in the log dissapered and then i made another try.
But this time i created two VPN connections.
The first one was for all my home/Private devices so i set it to strict policy and 192.168.xx.2/24, started it up and all devices went on the VPN without any problems.
The other one for my work laptop: I set YazFi to connect my work laptop to VPN2 and set it to force DNS from vpn provider. and forced it in to the tunnel.
They worked fine together and i was utterly impressed by running two VPN connections at the same time and routing private and work to different VPNs.
But then came the backside. Commercial everywhere and no more Skynet.
Diversion and Skynet stops working when i use the ovpn serviceproviders DNS.
After a little searching in this forum i found others with the same problem.
So with my home network i first tried to setup it up as Merlin and some others suggested with the VPN DNS setting to disabled, and also setting up CloudFlare DOT in WAN settings.
Unfortunately my vpn provider doesn't allow to disable the DNS settings or they don't work whithout me using their DNS servers.
So i got no internet connection and a constant restart of the ovpn client with a message in the system log with some error about "block-outside-dns".
So i turned off my Private Networks VPN connection, since i'm not concerned with my isp snooping on my internet traffic or anything like that.
I'm using the ISP that hosted PirateBay for the first years untill the Swedish Police heavily influenced and threatened by US goverment broke in to the ISPs server room and took The Piratebay servers out of there. The ISP refused to comply or let the Police or anyone get to their customers data so they had to force them self in to the server room.
They are all about privacy already and i don't have anything to hide privately so i'd rather have Diversion and Skynet protecting me than using a vpn tunnel for watching some streaming media that i pay for and doing everyday normal booring stuff like paying bills and reading emails from my childrens school.
It worked fine. So now im running the guest network on VPN 2 and my private Network with my ISPs settings.
My work laptop has always on VPN and running inside a VPN already so that's no issue that Diversion and skynet is not working for that.
And no more DCD Taunted errors either. I'm really not sure what was causing it. Since i did turn off all things related to Ai Protection. Traffic monitoring, QOS, web history, and all that and also removed my acceptance to Trends agreement already.
The only thing that has been causing errors is YazFi (but nothing serious) and my 5Ghz wifi 6 net I'm not so familiar with WIFI 6 and the correct settings. I only have a few devices connected to it but i get errors with bad frame packets that has something to do with Protected Management Frames not working properly. And some errors when changing the encryption keys. (I'm running WPA3-Personal).
My Xaomi supports wifi6 and wpa 3 but still it´s the one often causing errors in the log. my laptop only supports AC but it supports WPA3 so it works fine.
My Daughters ipad and iphone made me want to throw the devices out the window. They were constantly causing errors in the log, untill i removed the WiFi privacy that causes them to change MAC adress frequently.
That was something my Xaomi understood by itself since i have Lan MAC adress setting and Wifi MAC filtering set to "Accept" and have entered all devices in different ip blocks. It turned off its privacy mode and uses the phones MAC, but the Apple devices i had to turn it off manually.