Comment 49 for bug 1815101

> Now I need to have IP and gateway in two files - /etc/netplan/01-netcfg.yaml and
> /etc/systemd/network/10-netplan-ens160.network

to clarify, don't do that, you should create a systemd-networkd 'drop-in' instead of copying/modifying the file.

For example, if the networkd config filename for your interface is '10-netplan-ens160.network' (regardless of which directory it's located in), you should create a new file '/etc/systemd/network/10-netplan-ens160.network.d/override.conf' with only the content you want to add/modify, specifically in this case:

---
[Network]
KeepConfiguration=static
---

For more detail on systemd-networkd 'drop-in' files, see 'man systemd.network' in the first paragraph.