Below is the details of the error you are referring to :
Message: MAC address %m has declined address ⟨IP address⟩.
Meaning: The DHCP client has detected an IP address conflict and has declined
the specified address. (After a DHCP client has been offered an IP
address and before it accepts it, the client checks if there is any
other host using the same address. If the client does not find a
conflict, it accepts the address. If it does find a conflict, it rejects it.)
Action: No recommended action.
1: This doesn't seem to be an issue which should affect the DHCP
2: Are you seeing only one MAC address in this error or many ?
3: Any specific interval between two events? like some release time etc?
Thanks,
Vikas.