Yes I did, and the swappy machine started responding just a tad too slowly to other nodes' pings, engaging into a loop of join/parting the cluster, causing repl

Yes I did, and the swappy machine started responding just a tad too slowly to other nodes' pings, engaging into a loop of join/parting the cluster, causing replication to kick in all the time and a whole "highly available" critical cluster of 9 nodes was unable to handle traffic (too busy replicating) causing millions in losses. So yeah, don't use swap in servers. Ironically, if the node had crashed for OoM, the cluster would have survived just fine.