CheckMK version 2.0.0P1 vs CheckMK version 2.0.0p16 (CRE): Agent takes nearly double time to answer

You are sure that all the settings are the same? I don’t think so.
In your first graph i see already (also with the old system) a wrong configured agent. Normal agent response time takes 0.1 to 1 second not longer.
To say more about this problem the exact host config is needed.
From p1 to p16 are already many changes and you are sure that nothing important was shown at update time?