MongoDB pinging failed for distributed lock pinger caused by WriteConcernFailed:waiting for replication timed out. Error details: { wtimeout: true }
Your SECONDARY nodes are lagging on replication and your write concern dictates that write to the database should be acknowledged with X nodes, but before the system got enough acks, there was write timeout.

Check rs.printSlaveReplicationInfo() on all replica sets during time when you have hight load.