... This does not happen in clean profiles. ...
Thanks for your time guys.
No problem, I'll send you a bill...
If the problem doesn't happen with clean profiles, then the problem is probably not with the Kemper, your guitar or cable.
1. Isolate the Kemper from all external gear with only the power cable plugged in. Turn off all computers and monitors in the room.
2. Put on headphones, listen for noise.
3. Turn Kemper on, listen for noise (no guitar plugged in). If noise is heard, do a backup then a factory reset and listen again.
4. Plug in your guitar, listen for noise. If noise is heard, the problem is with the guitar or cable.
5. Continue connecting equipment one piece at a time (turn Kemper off while connecting) until you find the problem. Start with your interface and listen with headphones to both the Kemper and the interface, then connect to your computer, then your DAW.
The key is to listen to each piece of your chain to find what changes each piece is added. I think that's where your problem is because you say it doesn't happen in clean profiles.