This Forum Beta is ONLY for registered owners of D-Link products in the USA for which we have created boards at this time.
Yes, if your still using the 655 as the main host router then it will control the DCHP. Is the 860L running as a 2ndary AP? Do you have reserved IP addresses set up for each device on the 655?
Ok. You may need to factory reset, then turn OFF ALL devices. Save for one wired LAN PC. Do a IP reservation on the LAN PC. Then turn on one more device and do a reservation. Keep doing a reservation on graduating devices until all are reserved. I haven't seen this behavior before and presume this maybe a configuration issue. Keep us posted.
How many devices do you have connected total?