Hey Anjer, I know it's been a while since your last post, but have you heard back from Kemper Support regarding this?
I'm curious to know if you were able to find an answer or a solution for this?
I've packed my Kemper away for about a year due to the same issue. My tone is different from what it used to be in 2017.
Also noticed this after an update back in 2019.
I've updated again this week and still not happy.
Was able to use the editor to lower the "compression" for the amp on some of the profiles (same page where you can change Tube Shape, Tube Bias, Pick, Clarity, etc)
Then, also tried changing some of the main output's Low and High cut settings.
I might need to try loading an older Kemper OS version as a test.