quic: 

Whilst very early days, we are hearing some reports from customers using Ubiquiti devices (namely UDM's) which seem to be using the WAN DHCP lease with a 60 minute lease time, while we issue 20 minute leases. This causes the device not to renew its lease at the half-way point, and instead expire and get a new lease at expiry, which in turn causes a micro outage. We're not sure if this is a recent update or what at this stage.
We are acquiring one of these for our lab so we can interrogate it further, however if you feel you are impacted by this, feel free to see if you can work it out, or alternatively PPPoE is still always offered to avoid DHCP issues, even temporarily, until we get one of these in our lab to diagnose further.

With thanks to the folks here, and our beta testers for the influx of logs from primarily UDM's, we believed this bug (being DHCP not renewing correctly at halftime causing lease to expire and obtain a new lease) is now patched and resolved.