The Nintendo Switch has been observed to hold on to IP addresses even after
their expiration. My guess is that this is an oversight: likely the device
enters power saving mode with a configured IP address and just sleeps through
the expiration time.
As the device seems to wake up once every hour, we enforce a minimum lease time
of 1 hour, but only for affected devices. The rest of the network gets short
lease times.
https://twitter.com/zekjur/status/1263949112036282374