Loud squealing feedback

  • Not sure what going on here!! I’m new to the forum and to my Kemper so please bare with me. I’m just understanding the potential of my Kemper. My Kemper is unpowered, I used the performance selection and I was using the SVT bass profile when I needed to switch over from my NYC Sadowsky to my fretless bass (Both basses are active)...I switched Kemper selection over to tuner and unplugged my bass. Nothing happened...but when I plugged in my fretless and turned selector switch back to performance I got this loud squealing noise that wouldn’t stop even when volume knob was turned down!!! I quickly turned selector switch to tune and the squeal stopped. I turned it back to performance and got the same response....loud squealing!! This happened to me once before and I turned everything off...then rebooted Kemper and everything was fine after that. So, I rebooted Kemper and the squeal was gone. I played my fretless the rest of the day without any further issue. Has anyone had this issue and if so what is it I’m doing wrong? It’s so infrequent...it’s only happened once before....how or what did you do to correct the problem? Is it me?? Thanks!! ||