When starting up a Primary-Secondary-Arbiter configuration architecture, the warning messages regarding majority read concern enabled (implemented in
SERVER-37557) are not logged on any node. This is symptomatic of an issue with how we log warnings on startup that depend on the configuration of the replica set. Currently, we are attempting to log the warning before the nodes receive the configuration, and so we won't enter this 'if' statement.
If a node in a PSA architecture goes down and restarts, it will log the warning correctly. This should also apply to nodes on a clean startup, as well as on reconfiguration.