Comment 16 for bug 1775131

i have the same problem over here, i posted more details over here:
https://github.com/mailcow/mailcow-dockerized/issues/2918

i believe to reproduce the problem you can:
- set up multiple subnets under the same interface name
- make sure systemd-networkd is the only system to handle public interface (no NetworkManager or netplan)
- install somesoftware which uses networkd-dispatcher (like mailcow on docker)

- wait a week to see 1 minute downtime upon hitting the concurrency described above
OR
- my interfaces also restart (causing disconnets) upon systemd updates (via apt upgrade), or systemd re-install (with chances of 4 to 5 of hitting disconnect)

pls understand that to hit the concurrency problem you probably need to have lot's of IPs or subnets in your network configuration file in /etc/systemd/network/enpXXX.network (i got 7 ipv4 addresses there)

best regards, stan