It's impossible to make the KPA digitally distort, it can handle much higher numbers. I had made some maths time ago, now I've forgotten the results but believe me, the only things that can distort in the KPA are the analogic sections (i.e. before the A\D conversion and after the D\A conversion).
I'm guessing the Kemper is floating point within? Which makes it impossible to internally clip, but when going to 24 bit fixed you can easily clip. Converters and the spdif pipeline are 24 bit fixed. So, depending on the analog headroom at the DA stage, both digital and analog clipping can occur. Spdif will also clip.