Hi,
We have tried migrating the config from the 2860 router with firmware version 3.9.6/3.9.7/3.9.8 and restoring it on the 2865 router with firmware version 4.4.3.2/4.4.5 and we have noticed that the QOS page on 2865 is being broken.

After the config restoration, this is the page which we are getting on the 2865 :



We have tried this process on 4x different pairs of routers 2860 -> 2865 -  each time the result is the same.

This 'glitch' makes the 2865 router rather unpredictable.
So far we have seen cases where :
- after restarting the router via the WebGUI command - the router will freeze up and all the ethernet ports won't be powered up
- at random one or more ethernet ports will stop working on 1GB and will only do 100MB
- L2L VPN profiles cannot be fully set up with multiple subnets - getting strange error 'no more routes allowed'

Has anyone noticed any issues like that?

I have, but it's been a Browser issue for me. Clearing out Cache & Cookies (or switching to Private / Incognito mode) restored access.

Thanks for the hint - just tried the same router in Incognito Mode on multiple browsers. Still, the same error is present.
I still think its the config migration causing this.

In terms of QoS showing that error, it's a known bug in the latest firmware (if you're on 4.4.5.2). I have the exact same issue. There is a thread here discussing the problem:

https://www.draytek.co.uk/forum/routers-and-firewalls/25285-quality-of-service-control-panel-broken-on-2865ac-with-firmware-4-4-5-2-bt?start=0

Brilliant, thanks for the link to the other thread.
I will keep an eye for the new firmware and test it on all the affected routers. Will write here if this new firmware worked on my scenarios.