How many devices are getting addresses from the router? The conflict often occurs when everything is using DHCP, something goes to sleep, then the router reissues that address to something alse starting up or waling up, asking for an IP address, then the other client wakes up with the same address cached.
Among fixes, restart router often works, everybody has to ask for a new address, but sometimes that's just everybody awake. Some clients can figure out what is happening when they wake up, others are not so smart. I'm living alone, but still might have as many as 10-12 IP clients active, some better behaves than others.
I've cleaned up some of the conflict potential by having the router assign permanent addresses to permanently located devices, particularly those hard-wired like the desktop computer, network-attached drive, BluRay player, and to the printer's WiFi interface, because some of these need to be awakened by a network signal. I let my laptop and portable devices do DHCP because the portables are better behaved about waking up and the laptop is either on and busy or shut down.