Since we are observing every so often a failing reconnection attempt by Spark, we will conduct a review of the Smack reconnection mechanism and the detection of disconnection of Smack. It looks like Smack is a bit too nervous about the detection of network issue. Would include a patch in Spark 2.6.0 final, if needed and baked for at least two weeks in our production environment.
Any help or hint about reconnection/disconnection issues are highly welcome.