BEA-000150, Server failed to get a connection to the database in the past 30 seconds for lease renewal. Server will shut itself down.

We are using a Database-based lease renewal for automated server migration (I personally think it's a bad idea), we occasionally (once a month) have a server restarting with

BEA-000150 Server failed to get a connection to the database in the past 30 seconds for lease renewal. Server will shut itself down.

An Oracle DOC "With Database Leasing Server Migration WebLogic Servers Part Of Cluster Restarting Intermittently With Unable Renew Lease Errors [ID 1550164.1]" suggests that we should check for time skew in the different RAC nodes, which makes perfectly sense. However this is not our case. We shall keep investigating.