this.defaultSessionOpenOptions = withOptions();
this.temporarySessionOpenOptions = withOptions()

These two lines added in 5.4.5 in the org.hibernate.internal.SessionFactoryImpl constructor require the tenant to already be set, which it should not need to be at time of initialisation of the factory.

I suspect since the tenant identifier has been set at this time, it may also prevent switching of the tenant on creation of the connection using these defaults, although this is not certain.