Video here
Best example at 2:08 onwards playing on a clean and it just does the thing
It’s happening in all tracks simultaneously. Levels are not clipping.
Track 1: DI
Track 2: Miced Up Amp
Track 3: Output
Not sure what’s going on.
I’ve followed the USB audio routing from the NDSP website. And one (the one in the video) is on a fresh install of windows.
Can anyone help with this?
If I restart the unit as it’s happening, the issue goes away again, until it comes back.
Are you using MAC/PC? If PC are you using the current USB audio driver? Are you using CoreOS 2.3.0? Is your sample rate set correctly? Does your MAC/PC have enough resources?
I had the same issue. After a factory reset it never occurred again. Hopefully this helps you
PC, happening on all 3 PC’s.
USB Audio Driver: v5.58.0
CoreOS: 2.3.0
Sample Rate: 48Khz @ 24bit, 512 Samples
Using the same reaper template I created (only change IO’s on track routing) when I was recording from Headrush pedalboard ASIO/Interface.
Spec wise, they are more than suffice and even during recordings, the usage of the DAW does not exceed 5-8% of total CPU usage.
No other interface has given me this issue
PC1:
CPU: Intel Core i7-8650U
GPU: NVIDIA 1060 6GB
SSD: 256 SSD NVME M.2
RAM: 16GB of LPDDR3 RAM.
PC2:
CPU: Ryzen 5800x3d
GPU: NVIDIA 3060 12GB
SSD: 2TB SSD NVME M.2
RAM: 32GB of LPDDR4 RAM.
PC3 (Fresh install of windows and still occuring):
CPU: Ryzen 6800u
GPU: Integrated
SSD: 1TB SSD NVME M.2
RAM: 32GB of LPDDR5 RAM.
First thing I tried before posting, started happening within 30 minutes of recording again. 
Your resources look fine, I would recommend to backup (locally via Co Co or to the cloud), factory reset and restore to see if that resolves the issue. If not, recommend to email support@neuraldsp.com for assistance in troubleshooting your issues. We don’t hear USB audio related issues much any more so its rare and usually something to do with the PC/MAC. Also make sure you aren’t using any USB hubs as that can result with issues.
Thank you, I did try the factory reset first before posting. I just finished one again and now am testing again.
Have you tried using an alternate USB cable?
Yes,
I have 3 that I used, one has a Ferrite Core (Initially thinking it was maybe interference that was being picked up)
1x Original NDSP one
1x Cable with Ferrite Core (1m in length)
1x Cable w/o Ferrite Core (1m in length)
All exert the same symptoms on each PC
sounds like you’ve pretty much narrowed it down to a hardware issue, all your other specs look good. Have you contacted Support yet? They may need to repair your QC
I have not contacted support yet, was hoping there was something I was doing wrong because then this would end up being my second replacement unit then Since 12.23 
Understood. Support may also help you identify something corrupt or specific settings etc., worst case they can RMA if needed which hopefully isn’t the case.
Have been testing it again, looks like just peaking after 1 Hour and some odd minutes it starts occurring again,
Removing the USB and reconnecting USB seems to fix the issue, for another hour. Same for rebooting the unit.
Odd update, the sound now has travelled to the Output into the amp. Also is now happening within seconds of booting the unit.
I had a similar issue, I tried resetting the QC, I even replaced my ipad pro, I tried a different cable nothing helped! I ended up sending it back to Neural and they replaced the entire output board, but guess what! That did NOT fix the issue! Sweetwater sent me a new one at the end.
For me it was happening during playing as well, it was going crazy.
It used to happen while I was live streaming and people would call it “the aliens are coming!”…it was frustrating!
That’s sad to hear that the fix didn’t resolve,
I’m hoping your new unit hasn’t since caused you an issue?
Havent had any problems since. FYI I also swapped the USB cable with a USB-B to USB-C cable and I think it works better. Using a USB-C hub on my iPad Pro.
Below exactly the 3 parts I use. Haven’t had any issues for 6 months and I use my QC every day at least for 3 hours.
I bought that cable and tested it. Same issue.
I just got a new replaced unit, same issue.
I’m at my wits en d with this…
They replaced your QC and you are still having issues? Wow! I really don’t know what else might be! 
Are you using the original power supply?