If a node experiences machine slowness while initiating a replica set, then it could cause an unplanned election. If this happens while trying to stepUp a node, specifically after checking that all nodes agree on the applied opTime, then the stepUp could fail because the node stepping up may not have applied the new term oplog entry from the new primary. As a result, the intended primary will fail its election because the new primary is ahead of it and will vote no (this is specific to replica sets that will need the primary's vote to get a majority).

The stepUp function in ReplSetTest should have logic to retry the step up in such a case.