To respect the slot priority of the R710, PERC H700 need to be connected on the dedicated PERC slot (n°2 on the schema) into the RISER1.
It seems that you have try to slot the PERC H700 on the right connector. To avoid/remove this error, I could propose you to reseat the RISER1 and perform motherboard bios upgrade and PERC H700 bios upgrade.
If issue remain on the correct slot, this issue could be probably caused by a problem on the RISER1 hardware.
Stéphane Thiallier French Digital Solution Specialist Social Media and Communities Professional