DLNA/UPnP issues with network

I am using the following setup: DLNA library (miniDLNA running on Turris Omnia), DLNA renderer (Onkyo network player connected to Omnia using wi-fi or network cable), DLNA controller (BubbleUPnP android app on mobile phone connected to Omnia using wi-fi).
This setup was working pretty well for almost a year already by I noticed issues aprox. 2 months ago. In most cases renderer doesn’t see library and controller doesn’t see renderer on the network (very rarely it works, sometimes after switching off and on the renderer, or when renderer is freshly connected to wi-fi network in device setup, but still not 100% sure). First I suspected Onkyo issues after firmware upgrade, but then I connected old wi-fi access point (edimax) to Omnia via cable and connected renderer and controller both to this AP and suddenly everything works just perfectly.
Were there any changes in networking on Omnia, specially related to UPnP functionality? What can I change?
Is there any possibility to analyse the root cause? I tried Pakon but it didn’t give any relevant information.
I would be grateful for any kind of help.

I have a similar problem with Pioneer (Onkyo) network player connected to Turris 1.1 via cable/wifi. My NAS (WD MyCloud) lost connection after short time resp. Pioneer doesnt see server.

It seems that there is some problem with wi-fi in Omnia (both 5GHz and 2,4GHz cards). When I connect Onkyo via cable and mobile phone using external access point connected to Omnia, it works perfectly.

I have similar problem with Onkyo after update of new firmware.
I guess it is with this new firmware I have to unplug the Onkyo (hard reset) then after switch on everything works fine. The DLNA server is visible.
The Onkyo is wired to Turris Omnia (no wifi is using).