SERVER-37631 changed sharded cluster setup so that it's required to run refreshLogicalSessionCacheNow on the config server followed by each mongos. Only then will each 3.6 mongos correctly report logicalSessionTimeoutMinutes in its isMaster responses.
Without performing this workaround the cluster appears usable, but does not report logicalSessionTimeoutMinutes so sessions are not enabled in drivers.
SERVER-37631 changed sharded cluster setup so that it's required to run refreshLogicalSessionCacheNow on the config server followed by each mongos. Only then will each 3.6 mongos correctly report logicalSessionTimeoutMinutes in its isMaster responses.
Without performing this workaround the cluster appears usable, but does not report
logicalSessionTimeoutMinutes
so sessions are not enabled in drivers.