Hey there, I'm coming to ask if I should file a bug report and if so, where.
There's a problem using OpenWRT with Starlink. Long story short; when the Starlink dish ("Dishy") reboots, it temporarily hands out an IP address of 192.168.100.100 to the router connected to it. That DHCP lease has a 5 second expiration. Once Dishy has finished configuring itself it will hand out a final IP address that is your real address, something in the CgNAT 100.64.. block.
OpenWRT isn't ever getting this second address. Instead, it keeps renewing the 192.168.100.100 lease. A lot of routers seem to have this problem, so it could be a bug with Starlink's DHCP server. Or it could just be OpenWRT reacting badly to the weird super-short 5 second DHCP lease.
I finally caught my router in this bad state and got some logs that suggested OpenWRT was ignoring the 5 second lease expiration. Details on my blog at https://nelsonslog.wordpress.com/2021/04/07/openwrt-vs-starlink-dhcp-leases/
Is this a bug I should file against OpenWRT? If so, is it core, udhcpc (Busybox), or netifd?
I'm also open to any advice on how to further debug the problem. Unfortunately I didn't have tcpdump installed at the time so couldn't capture the DHCP traffic. Next time!