R7960P DHCP - duplicate IP assignments

R7960P / Firmware 1.1.2.84_1.3.42

From the web ui, Advanced->Setup->LAN Setup, I reserved a number of IP addresses within the DHCP range. As I understand it, the DHCP server should assign reserved addresses only to corresponding MACs; with other devices assigned non-reserved addresses within the IP range.

I'm having a recurring situation, where an IP address is assigned to a mismatched MAC; and ALSO where a reserved IP address is assigned to multiple MACs.

My NAS has wired connection to my EX8000 extender.  10.0..0.117 is reserved for my NAS MAC. In the attached devices table, 10.0.0.117 appears twice: with the NAS MAC (expected); and duplicated to the extender's 2.4G MAC. See attachment.

The duplicate assignment BLOCKS my NAS' cloud access features.

I believe this is a significant firmware defect. Any ideas? 

As an aside, notice that 10.0.0.107 shows (2) attachments - both incorrect, since 10.0.0.107 is reserved for a different MAC entirely.