My guess is that the client device connects, gets given 0.2 but then fails to renew the lease before expiry. Something else comes along and the DHCP implementation in the router gives it the lowest currently-free address. Your client then detects the clash and asks for another IP address. Some DHCP implementations will attempt to reserve an IP address for a particular MAC and will only re-use one if it runs out of spare addresses.
I hardwire my DHCP to dish out known fixed addresses to the known devices on the network and have a small dynamic pool for new devices. A quick check shows that my home network has accumulated 50 different known devices, although some of those are now defunct and some are virtual machines.