This is normal. Your syncthing instance connects to a relay hosted by someone. Relays are provided by other users and they can run them on whatever port they like - this particular relay runs on port 22, the default port is 22067.
The list of all public syncthing relays is here: https://relays.syncthing.net/
As you can see, the IP address 188.8.131.52 port 22 is a relay, provided by “https://keybase.io/rany”.
You can fully disable relays if you like, or host your own private relay. Relays are usually slower anyway and are only intended as a fallback. You should always attempt to make your setup work without relays, if possible.
PS: Port 22 is the destination port. On Linux binding to a port < 1024 usually requires higher privileges, but the bind port equals the source port on outgoing data. The destination port is unaffected and as such any application may connect to a port < 1024 as long as the firewall let’s it through. Some users run their relay on port 443 to pass more firewalls, as this port is usually not blocked (https).