I’m using the UR816C and when I turn my output up past halfway, I get this terrible feedback from FL Studio regardless of which mics are armed to record or not. I also have occasional lag issues when using a NI Komplete Kontrol S49 or sometimes even just from Spotify. I’m guessing this is just some interface setting I haven’t found, so I appreciate any help I can get.
Maybe your recording channels are going to the output of your DAW, which means they are heard via the DAW channel in the Dspfxmix and also audible through the inputchannels of the URC, so there is a loop.