Strange 2.9 DHCP w/relay Issue

Got a 2.9 MT running DHCP Server, and have several other boards running DHCP Relay. Kinda weird, but some of the clients, not on the same interfaces, not on the same DHCP Relay routers, they get a 3 day lease. Once the expires counts down to 2d 23h 58min, it RENEWS! So it shows 2 23 59 , then it counts down to about the same 2 23 58 then it renews again! . Different customer routers etc..

Several different routers at the customers, so not a router issue to one brand. It is not like its not working, but it just is more traffic and more traffic.

Anyone else see this?