Recently, I have a problem when recording, at random, the same channel I record into something like such a self-feedback and start screaming. Once I play with the inputs on f4-audio connections, it works out until next time. audio file of the problem— 
https://drive.google.com/open?id=1IRDFCUvcdcV9-qAewuXxQMd9iomWCbBP
cubase 9.5 -64bit
MAC os x El Capitan 10.11.6
rme fireface uc400
tnx for help