Client log file filled with - ClientService cmd: PONG

The /var/log/urbackupclient log file is filled with “ClientService cmd: PONG” lines.
My other Linux client doesn’t not have them.

One is entered every minute.

2018-01-26 11:20:27: ClientService cmd: PONG
2018-01-26 11:21:27: ClientService cmd: PONG
2018-01-26 11:22:27: ClientService cmd: PONG

I am assuming this is a problem.
Does anyone know how to fix it?

I reinstalled the client (tried different versions) but log still fills with the message, one every minute.
My other client (on the server) doesn’t do this.

Any idea what is wrong?