After connectors rebalance the MySQL source connector fails to restart and throws the error attached. It seems that the connector blocked itself, it tried to connect to binlog but it hasn't disconnected cleanly before that.
The version of MySQL is 5.7.22. This is the only MySQL connector running in the cluster, all the others are MongoDb. The connector is already running for a few months correctly, error appeared after upgrade to 0.9.0.Final.
I did not get the error to appear locally when there is no database traffic.
Source connector example: