Steinberg UR824 Hybrid Routing - Need help!

I bought the UR824 a couple of weeks ago because I needed the ability to have 24 channels out to my 24-channel mixing board as I’m mixing hybrid with a lot of outboard gear. Before this, I used the Behringer U-Phoria 1820 UMC but had only 16 channels out. Therefore the switch.

I love the interface and it works gloriously for the most part BUT I’m now stuck in somewhat of a problem that I just can’t seem to get my head around. When I output on all 8 channels of the interface + 16 channels from to Ultragain ADATs I want to mix on my desk using my outboard gear but when I get to printing in all back into my DAW using a stereo pair of in’s on the UR824 I get a terrible feedback as it sends in the input back out to my console creating a feedback loop. I have tried working with the control panel to cut of the output of the channels, but then, as you would expect, the mixer does not recieve some of the channels making it impossible to mix and print back into my DAW using this interface. Or so it would seem.

I feel I’m pretty experienced in working hybrid at this point but I’ll have to admit that this has thrown me a bit of course wondering if working hybrid is even worth it anymore.

Is it possible to output on all 24 available channels and still be able to print a stereo signal back into the UR1820 without getting feedback? On the U-Phoria 1820 it worked flawlessly even though I used all 16 outs at the same time, so I don’t understand why this is happening. I’m sure there’s something that I’ve missed but reading manually three times hasn’t helped either.

Can somebody help or point me in the right direction?