This looks like a HF compensation issue.
Sorry but it is NOT a compensation issue, despite how it looks.
This poll and thread is about a hardware problem with the Rigol MSO5xxx scope - where overshoots are present on some or more channels, or not, same, different probes etc, and cannot be adjusted away. Some users have replaced an lfcal.hex file on the scope and it's been fixed, some have returned and have replacement mainboards and fixed. Some have had no problems at all (the majority by the poll so far).
I am just trying to gauge how many people have the same problem, or not as the case may be as Rigol seemingly have an issue with factory calibration.