After I upgraded tot the latest 6.31 version and installed it, I get in the logs every 30 second an entry: excessive broadcast / loop message op the modem port (port 1) on the RB2011UAS. I never had this before! Nothing was changed (physically).
Although my other two Mikrotik (RB912UAG-5HPnD) and RB951-2n were also upgraded, and they do not show any problems.
I must say that everything works, internet and the VPN are up.
Resolved by downgrading to 6.30.2.
Is this a new problem?