Message "Recovery HD is mounted successfully" flashes everytime I connect or disconnect from any VPN service

I am seeing the message(s) flash in a box on top right corner for a while now.

Let's say I connect to any VPN connection, I see the message "Recovery HD is mounted successfully" then a few seconds later, I see another message flashing by "Recovery HD is unmounted successfully".

Any clue what is causing this please?

Thanks !